"Stop making cookies."
I'm sorry, what was that dear?
"I said, stop making cookies."
That's odd, I thought to myself. Why would she be saying that? Wouldn't any wife be pleased to be married to a husband who fills the house with the aroma of warm butter, caramelized sugar, and gooey chocolate? Indeed, wouldn't any human being in the right mind yearn to be constantly surrounded by sweet, crisp-and-chewy snacks?
Then, as I glanced around the apartment, wiping chocolate-specked hands against my apron, running a finger across the countertop and tracing a line into the dusting of white powder that coated every surface in the kitchen, eyeing the dozens of bags of failed experimental cookies that blocked the television, opening the refrigerator door to discover that more than half of its contents were batches of uncooked cookie dough in various stages of rest, I thought, maybe she does have a point.
For the past few months, I've had chocolate chip cookies on the brain. I wake up in the middle of the night with a fresh idea, a new test to run, only to discover that my 10 pound flour bin has been emptied for the third time. Did I really use it all up that fast? I'd put on my coat and walk out in the cold New York winter night, my sandals leaving tracks in the snow as I wander the neighborhood, an addict searching for a convenience store that will sell me flour at 3 in the morning.
You see, I've never been able to get a chocolate chip cookie exactly the way I like. I'm talking chocolate cookies that are barely crisp around the edges with a buttery, toffee-like crunch that transitions into a chewy, moist center that bends like caramel, rich with butter and big pockets of melted chocolate. Cookies with crackly, craggy tops and the complex aroma of butterscotch. And of course, that elusive perfect balance between sweet and salty.
Some have come close, but none have quite hit the mark. And the bigger problem? I was never sure what to change in order to get what I want. Cookies are fickle and the advice out there is conflicting. Does more sugar make for crisper cookies? What about brown versus white? Does it matter how I incorporate the chocolate chips or whether the flour is blended in or folded? How about the butter: cold, warm, or melted?
So many questions to ask and answers to explore! I made it my goal to test each and every element from ingredients to cooking process, leaving no chocolate chip unturned in my quest for the best. 32 pounds of flour, over 100 individual tests, and 1,536 cookies later, I had my answers.
How Cookies Crumble
Most traditional chocolate chip cookie recipes start with the same basic ingredients and technique: butter and sugar (a mix of white and brown) are creamed together with a touch of vanilla until fluffy, eggs are beaten in one at a time, followed by flour, salt, and some sort of chemical leavening (baking soda, baking powder, or a bit of both). The mixture is combined just until it comes together, then spooned onto a baking sheet and baked.
When you bake a cookie, here's what's going on, step-by-step.
- The dough spreads:. As the butter warms, it slackens. The cookie dough begins to turn more liquid and gradually spreads out.
- The edges set: As the cookie spreads, the edges thin out. This, coupled with the fact that they are fully exposed to the heat of the oven and are constantly reaching hotter areas of the baking pan, causes them to begin to set long before the center of the cookie does.
- The cookie rises: As the butter melts and the cookie's structure loosens, this frees up water, which in turn dissolves baking soda. This baking soda is then able to react with the acidic components of brown sugar, creating gases that cause the cookies to rise up and develop a more open interior structure.
- Egg proteins and starches set: Once they get hot enough, egg proteins and hydrated starches will begin to set in structure, finalizing the shape and size of the finished cookie.
- Sugar caramelizes: At its hottest areas—the edges and the underbelly in direct contact with the baking dish—sugar granules melt together, turning liquidy before starting to caramelize and brown, producing rich, sweet flavors.
- The Maillard reaction occurs: Proteins in the flour and the eggs brown along with the sugar in a process called the Maillard reaction—the same reaction responsible for giving your hamburger or bread a brown crust. It produces nutty, savory, toasted flavors.
- The cookie cools. Once it comes out of the oven, the process isn't over yet. Remember that liquefied sugar? Well as the cookie cools, that liquid sugar hardens up, which can give the cookie an extra-crisp, toffee-like texture around the edges. Meanwhile, the air inside cools, which causes the cookie to deflate slightly, though when fully baked, the structure lent by eggs and flour will help it retain some of its rise.
It's a simple technique that hides more complicated processes underneath. So how do you decipher what's going on? My first course of action was to test out these basic ingredients one at a time in order to determine how they affect the final outcome.
Butter is where most recipes begin, and it provides several things to the mix.
It keeps cookies tender. When flour is mixed with water (such as the water found in eggs), it develops gluten, a tough, stretchy network of interconnected proteins that set up as they bake. Gluten can't form in fat, thus butter will inhibit its overall formation, leading to more tender results. The higher the proportion of butter to other ingredients, the more tender your cookie will be (and consequently, the more it will spread as it bakes). I found that a ratio of 1 part flour to 1 part sugar to .8 parts butter was about right for a cookie that spreads moderately but doesn't end up cakey.
Cookie Fact #1: More Butter = Wider Spread and More Tenderness
Butter is essential for flavor. Substituting butter with a less flavorful fat like shortening, lard, or margarine yielded sub-par cookies. Butter is about 80 to 83% butterfat, 15% water, and 3 to 5% milk protein. These proteins brown as the cookie bakes, adding nuttiness and butterscotch notes to the final flavor of cookies.
Cookie Fact #2: Butter Gives the Most Flavor
Because of shortening's different melting qualities (and the fact that it has no water content), shortening-based cookies come out softer but more dense than those made with butter.
How butter is incorporated can also affect texture. In the early creaming stages of making a cookie, cool butter is beaten until it's light and fluffy. During the process, some air is incorporated and some of the sugar dissolves in the butter's water phase. This air in turn helps leaven the cookies as they bake, giving them some lift. Melting butter before combining it with sugar and eggs leads to squatter, denser cookies.
Cookie Fact #3: Melted Butter = Denser Cookies, Creamed Butter = Cakier Cookies
I asked myself: if browning milk proteins provide extra flavor to cookies, how could I boost that flavor even more?
My friend Charles Kelsey, the man behind the fantastic Brookline, MA sandwich shop Cutty's, developed a simple chocolate chip cookie recipe for Cook's Illustrated magazine back in 2009. In his recipe, he made the ingenious discovery that browning the butter before adding it to the mixture would give the cookies a much more pronounced nuttiness.
But this created some other problems. Since the butter can't get hot enough to brown milk proteins until all of its water content has evaporated, brown butter adds no moisture to dough. This produces a couple of interesting results. Without water, sugar that is mixed into browned butter cannot dissolve (sugar molecules are highly hydrophillic and will dissolve readily in water, but not in fat), which makes it subsequently more difficult for them to melt into each other as the cookie bakes. The cookies ended up missing out on some of that caramelized toffee flavor I was after.
Cookie Fact #4: Less Dissolved Sugar = Less Caramel Flavor
With less water, you also end up with less gluten development, thus a cookie made with browned butter is softer and more tender than one made with creamed or plain melted butter. Soft and chewy is good, but I wanted a slightly better balance.
Cookie Fact #5: Creamed Butter = Lighter and Firmer, Melted Butter = Denser and Chewier
So how do I get the flavor benefits of browned butter while still allowing for sugar to dissolve and caramelize properly? The answer turned out to be in the eggs.
Before we jump to the solution, let's take a quick look at what eggs have to offer in a cookie.
Egg whites provide a good amount of water, as well as protein. Egg proteins are particularly good at trapping and retaining bubbles of air or water vapor. The higher the proportion of egg white in a cookie, the more it rises during baking. Because of the extra water, you also get more gluten formation, which again leads to a taller cookie (provided you use enough flour to absorb that extra water). Other than the small amount in the butter, eggs are the main source of water in a cookie dough recipe.
Egg yolks also provide some moisture and protein, but more importantly they provide a well-emulsified source of fat. When cooked, egg yolk forms a tender protein coagulum that can keep cookies tender and fudge-like. A high proportion of egg yolk leads to a more brownie-like texture in a finished cookie.
By keeping the total mass of egg added to a dough the same but altering the proportion of white to yolk, you can achieve a variety of textures. Two whites and a yolk, for instance, produces the more open structure of the top cookie in the photo above, while three yolks and no whites produces the denser, fudgier texture of the cookie on the bottom.
Cookie Fact #6: Extra Egg Whites = Taller Cookies. Extra Egg Yolks = Fudgier Cookies
Turns out that the combination I like best is actually a 1 to 1 ratio of egg whites to egg yolks, which conveniently is exactly how eggs naturally come. Ain't that something?
Going back to my initial problem of wanting the flavor of browned butter but disliking the way it prevented sugar from properly dissolving, I asked myself, what if I were to flip the script for these cookies: instead of creaming sugar and butter and adding eggs, why not beat together the eggs and sugar then add the butter?
I tried it, beating brown sugar, white sugar, and vanilla with whole eggs in a stand mixer until the mixture became pale, aerated, and ribbony, with a nearly completely smooth texture.* To this, I added my browned butter, which instantly cooked the eggs and curdled them, turning the mixture into an oddly sweet and vanilla-y scrambled egg custard. Lesson learned: let that browned butter cool before adding it.
*A sugar and water solution becomes fully saturated at room temperatures at a ratio of about 2 parts sugar by mass to 1 part water (that is, you can't dissolve any extra sugar because it will stay granular). My working recipe contained about 4 ounces of egg and 10 ounces of sugar, so perfect smoothness was an impossible goal.
My next attempt with cooled brown butter fared better, but the finished cookies ended up with an oddly uniform texture and a relatively smooth top rather than the cragginess I'd been getting earlier.
Turns out that you actually want a balance between dissolved sugar and undissolved sugar to keep things texturally interesting.
Cookie Fact #7: Too Much Dissolved Sugar = Uniform Texture and Less Cracking
I settled on beating half of the sugar with the eggs until it completely dissolved, then incorporating the rest when I added the brown butter. The degree to which the butter is cooled before adding it to the mix can also affect how well it holds air when being mixed with the eggs. Warm butter flows very easily and doesn't trap bubbles well. The cooler it is, the more viscous it becomes, and the better it can trap air. Even a few degrees can make a difference. By letting my browned butter cool down until it was almost at room temperature, it became firm enough to beat into the egg and sugar mixture without deflating it.
Cookie Fact #8: The Warmer the Butter, the Denser the Cookie
In order to get my browned butter to chill a little faster and to add back some of the moisture that's lost in the browning process, I discovered that whisking an ice cube into it after cooking killed both birds with one stone.
There's more to sugar than just sweetness! The type of sugar you use and its method of incorporation can have a profound effect on the finished cookies. White sugar is crystallized sucrose, a disaccharide consisting of a fructose molecule and a glucose molecule linked together. It is mildly hygroscopic (that is, it likes to retain moisture), and relatively neutral in pH.
Brown sugar is mostly crystallized sucrose, but also contains a good amount of glucose and fructose, along with trace minerals that give it its flavor and a slightly acidic pH. Glucose and fructose are far more hygroscopic than sucrose.
Check out what happens if you bake cookies that are made 100% with white sugar or brown sugar:
Cookie Fact #9: White Sugar = Thin and Crisp, Brown Sugar = Tall and Moist
A mixture of the two provides a good balance, and as I noticed in my egg tests, dissolving too much sugar can lead to a texture that's too uniform. With sugar left in distinct grains, the pockets of melted sugar that caramelize within the cookie as it bakes remain irregular, giving the cookie more textural interest.
But brown sugar has another advantage over white: it caramelizes more readily, leading to more intense flavor. I wondered: could I bump up the intensity of the toffee flavor while still maintaining a good white and brown sugar balance by pre-caramelizing some of my white sugar?
I tried it, heating my white sugar up in a pot until it was a golden amber before adding cold butter to rapidly chill it and then incorporating it into my dough.
No dice. First off, it's a mess trying to scrape hot caramel out of a pan and prevent it from hardening into a single massive clump. Secondly, it made my cookies far too soft and chewy (I recalled that in the process of caramelizing sucrose, it breaks down into glucose and fructose, acquiring their hygroscopic properties).
A much simpler way was to blend only the white sugar with the eggs so that it was pre-liquefied, giving it a little jump start on caramelization, then adding in the brown sugar later on with the melted butter.
Incidentally, if you want the absolute chewiest, most uniformly textured cookies, try replacing some of the white sugar with corn syrup, a sugar that is even more hygroscopic.
You end up with wide, flat cookies that stay soft and flexible even when completely cooled. Not only that, but since corn syrup is made up of simpler sugars than granulated sugars, it caramelizes more readily, leading to darker overall color.
Cookie Fact #10: Corn Syrup = Soft, Wide, Dark, and Flexible Cookies
Corn syrup is so darn powerful, in fact, that even a small amount of it will completely alter the texture of your cookie. In the cookies above, the batch on the left was made with 5 ounces each of white and brown sugar. The batch on the right was made with 5 ounces of brown sugar, 4 ounces of white sugar, and 1 ounce of corn syrup. A substitution of only 10%.
Next up: baking soda and baking powder.
Leavening—the introduction of air to the internal structure of baked goods—can come in many forms. In bread, it's the carbon dioxide produced by yeast. In a cream puff, it comes from expanding water vapor. In the case of cookies, we get it from egg proteins capturing expanding gases, creamed butter, and most importantly, chemicals, namely baking powder and baking soda. What's the difference between the two?
Baking Soda is pure sodium bicarbonate—an alkaline powder (aka, a base). When dissolved in liquid and combined with an acid, it rapidly reacts, breaking down into sodium, water, and carbon dioxide.
Baking Powder, on the other hand, is baking soda with powdered acids built right in. In its dry state, it's totally inert. But once you add a liquid, the powdered acid and base dissolve and react with each other, creating bubbles of carbon dioxide without the need for an external acid source. Most baking powders these days are double acting, which means that it contains two different powdered acids. One that reacts immediately upon mixing with water, and another that only reacts after it's heated, giving cakes and cookies a little boost early on in the baking phase.
Making cookies with varying degrees of both soda and powder, I found that baking powder generally produces cakier cookies that rise higher during baking, producing smoother, shinier tops, while soda yields cookies that are craggier and denser in texture
Check out this post for more on the differences between baking powder and baking soda.
Cookie Fact #11: Soda = Craggy and Coarse, Powder = Cakey and Smooth
Cakey cookies are not for me, and the brown sugar I was using in my cookies provided plenty of acid for the baking soda to react with. I landed on 3/4 teaspoon as the right amount. Moreover, because the Maillard reaction takes place more readily in mildly alkaline environments, baking soda has a powerful effect on how rapidly foods darken and develop browned flavors. Browning is a good thing when it comes to cookies.
The main differences in flour varieties comes down to protein content. Cake flour contains a relatively low amount, which leads to less gluten formation. Cookies made with all cake flour will be very soft, almost mushy, even when you've cooked them to what would normally be a beyon-crisp stage. All-bread-flour cookies, on the other hand, come out ultra-chewy. Alton Brown has a recipe called The Chewy which utilizes this effect.
Cookie Fact #12: More Bread Flour = Chewier Cookies, More Cake Flour = Softer Cookies
The infamous Jacques Torres recipe from The New York Times calls for a mixture of low-protein cake flour and high-protein bread flour in an attempt to balance the two. I found that by working carefully with the ratio of other ingredients, you can get away with using regular old all-purpose flour with no problem.
Since flour provides the bulk of the structure in a cookie, the amount you use can alter the texture of the cookie. A small amount of flour compared to butter (a ratio of 1 to 1 or less) will give you cookies that spread out into a wafer-like lace cookie. Extra flour (a ratio of 1.3 to 1 or higher) will give you cookies that barely spread at all as they bake, with centers that stay dense and dough-like, even after being almost fully cooked.
This may be a good thing for some folks, but I like my cookies to have a nice balance between the two. I settled on a ratio of 10 ounces flour to 8 ounces of butter.
Cookie Fact #13: Less Flour = Lacier Cookies, More Flour = Doughier Cookies
Turns out that how you incorporate that butter also makes a difference (are you sensing a theme here? When it comes to cookies, apparently EVERYTHING MATTERS).
The dough above was made by really working the flour into the butter and egg mixture before subsequently folding in the chocolate chips. As you can see, it comes out very smooth and it bakes into correspondingly smooth cookies. Because extra kneading creates a stronger gluten network, the cookies also end up rather tough.
Much better is to barely work the flour in, folding it or mixing it with a stand mixer until it just pulls together into a dough. I incorporate the chocolate half way through this process, so that I don't accidentally overmix the dough while trying to fold the chocolate in.
Cookie Fact #14: Less Kneading = Craggier Cookies and Better Texture
The resultant scoops of dough should have a natural cragginess to them even before baking.
If you like extra craggy cookies, Baking Illustrated offers a neat tip for increasing that cragginess: tear the balls of dough apart with your fingertips and moosh'em back together with the jagged torn part facing outwards.
Provided you've used enough flour and your other ratios are spot on, those crags should appear in the cookies' final baked form.
When I first started testing, I figured that the only real question when it came to chocolate would be what brand and what cacao percentage. Turns out that how the chocolate is incorporated can also affect texture.
Chocolate chips produce the most regular cookies, with small, melty pockets of chocolate. Chocolate discs and chunks will cause some degree of layering in the dough, creating a flakier cookie with larger sections of molten chocolate. Chopped chocolate produces the most contrast—the small bits of debris and chocolate shavings get dispersed throughout the cookie dough, disrupting its texture and giving a nice chocolatey flavor to the whole affair, while larger chunks still melt into large gooey pockets. The only way to get this effect is to hand-chop whole chocolate bars with a knife.
Cookie Fact #15: Hand-Chopped Chocolate = Most Intense Flavor and Interesting Texture
Hand chopping also gives you control over the exact size of your chocolate chunks. I quickly discovered that I like quite a bit of chocolate (a full 8 ounces), and I like it in large, 1/2- to 1/4-inch chunks.
I spent an awful lot of time experimenting with how the temperature of the dough during chocolate incorporation can affect the final outcome of the cookie. Properly tempered chocolate (if you're a chocolate nerd, I'm talking chocolate with type V crystals) will melt at a relatively high temperature—around 95°F or so.
By incorporating chocolate into dough that's been allowed to rest in a warm spot until it gets above 95°F (near my preheating oven worked), or by gently stirring already-made cookie dough that's been warmed to above 95°F, you end up dispersing some melted chocolate throughout the works.
The result is a sort of swirl effect that can be quite delicious if you do it carefully, though you miss out on the classic large melty pockets.
I quite like cookies made with dough that has been warmed to 80°F and gently swirled. This melts the very tiniest bits of chocolate, but leaves the larger chunks intact.
Cookie Fact #16: Stirring Warm Dough Alters Chocolate Dispersal
In the interest of not being labeled a total neurotic, I decided to leave this particular step out of the final recipe, but if you're anything like me, you'll wait until everyone leaves the kitchen before pulling out the thermometer you keep in your back pocket to test the temperature of your dough before folding it.
Ok, we've been at this for a while. Time for a quick recap. So far we've covered butter, sugar, eggs, leavening, flour, and chocolate. As far as covering the major chemical and physical players in the cookies' final outcome, we're done.
Here's what we're working with so far: White sugar is beaten into whole eggs until it dissolves. Butter is browned and chilled with an ice cube to add back lost moisture and hasten its cooling, before being beaten into the egg mixture, along with brown sugar flour and baking soda are folded in very gently, along with chocolate.
Cookie Fact #17: Cookies Need More Salt Than You Think
Salt (and quite a bit of it) is essential to balance the flavor of caramelized sugars, and a good amount of vanilla is a must (though, as our recent taste test has shown, even imitation vanilla flavoring will do just fine).
Cookie Fact #18: Inexpensive Vanilla is Indistinguishable From Fancy
Even with regular salt mixed into the dough, I like adding a little sprinkle of coarse sea salt to the tops of the cookies, gently pressing it in right as they come out of the oven for little crunchy bursts of salt that pop with each bite.
With flavor and ratios out of the way, it's time to talk thermodynamics.
We've already seen how the temperature of the dough can affect how chocolate is incorporated, but it can also affect how it bakes. Both the starting temperature of the dough and the oven temperature have an impact.
I baked cookies at various temperatures in 25°F increments ranging from 250°F up to 450°F. When baked at a lower temperature, the dough has more of a chance to spread out, leading to flatter, wider cookies. Conversely, cookies baked at higher temperatures spread less. Even a difference of as little as 50°F makes a big difference.
Moreover, the lower the oven temperature, the more evenly the cookie bakes, with less of a contrast between the edges and the center. In fact, when the oven temperature gets low enough (around 275°F and below), you completely lose any contrast, producing a cookie that's more or less homogenous across the board.
Cookie Fact #19: Cooler Oven = Wide Cookies. Hotter Oven = Compact Cookies
Beyond oven temperature, starting temperature of dough also affects the outcome.
As you can see, cookies cooked straight from the fridge will stay a little more compact, while those that are allowed to warm will spread more. By adjusting the starting temperature of the cookie dough and the temperature of the oven, you can create a wide variety of textures and contrasts.
Cookie Fact #20: Warmer Dough = Wide Cookies, Cooler Dough = Compact Cookies
I like the flexibility that being able to cook cookie dough straight from the fridge lends you, so my recipe is designed to make cookies from dough that starts at 40°F. I found that baking in a 325°F oven until the edges are nice and toasty brown will leave you with a cookie that's still plenty soft and chewy in the center.
Giving it a Rest
You still here? I haven't bored you with cookie talk yet? Good, because we're coming round third base and into the home stretch here. But not so fast. We gotta take our time with this one. Literally.
Back when the New York Times published that Jacques Torres recipe in 2008, I'd never heard of the concept of resting a cookie dough, yet Mr. Chocolate himself insisted that it was the secret to better flavor. Since then, I've talked to several pastry chefs and cookie experts who all agree: letting your cookie dough sit overnight in the refrigerator produces better tasting cookies.
It seems a bit finicky (and honestly, who wants to wait for cookies?), but after trying it dozens of times, the results are absolutely undeniable.
If there's one single thing you can do improve the flavor of your cookies, it's to let the dough rest. They bake up darker and more flavorful. That butterscotch note that was barely hinted at when you baked the dough right after mixing? It'll blow you away with its intensity and complexity by the second day.
So how does it work? Harold McGee explains it in Keys to Good Cooking. Turns out that during the resting process, both flour proteins and starches break down a bit. How does this help improve flavor?
It helps to think of proteins and starches as large LEGO structures. During the process of browning, those large structure are broken down into smaller parts and individual pieces and subsequently rearranged. Sort of like destroying that LEGO castle so you can build a dozen spaceships. Now, both of these phases—the breaking down and the reconstruction—take time.
By resting the dough, you give the deconstruction phase a head start. It's as if you left your LEGO castle sitting out over night and your annoying little sister came by and smashed it all, King of Tokyo-style. With the pieces separated, building your spaceships is much faster.
It's really the same thing, except instead of LEGOs, you've got proteins and flour. Instead of an annoying sister, you've got enzymes. And instead of awesome spaceships, you get awesome cookies. How awesome? We're talking, oh, a million puppies on the moon wearing superhero underpants under their little doggie spacesuits levels of awesome.
Cookie Fact #21: An Overnight Rest Yields Superior Flavor
And while it's tough to be patient, awesomeness is something worth waiting for in my book.
When all is said and done, my final recipe has ended up combining some unique techniques from a couple of my favorite recipes—the browned butter from Charles Kelsey's Cook's Illustrated recipe and the resting from Jacques Torres' New York Times recipe—along with a couple of my own novel twists—dissolving half the sugar in the eggs and chilling the melted butter with ice before incorporating—to produce a cookie that hits all the right notes. A deep, rich, butterscotch-and-toffee flavor, crisp edges, and a soft, chewy center, an irregular crumb structure with a craggy top, and a mix of chocolate dispersed through the cookie in fine threads and big gooey pockets, all with a nice sweet-and-salty balance.
Are they the simplest cookies in the world? No way. Are they worth the extra time and effort? I certainly think so.
"This is the last batch, I promise," is what I told my wife about a week ago. Since then I've gone through another 10 pounds of flour. Heck, if you want to know the truth, I've baked four batches of cookies while I was writing this article, which means that even as I hit that "publish" button, this recipe is already obsolete, a work in progress. My wife went to bed over 5 hours ago and left by giving me a gentle hug from behind and a soft whisper in my ear: "Please stop making cookies."
The beauty of understanding how ingredients interact with each other is that even if my definition of the "best" chocolate cookie isn't in line with yours, if you've come along this far, then you know what you need to do to adjust my recipe to suit your own tastes. Like your cookies chewier? Substitute some of that all-purpose flour for bread flour. Want your cookies to rise up a little taller? Add a touch of baking powder or replace the yolk of one of those eggs with an extra white. You like your chocolate in distinct pockets? Just use chocolate chips instead of hand-chopped. Want your cookies more flexible and chewy? Just replace some sugar with a touch of corn syrup.
You get the idea. Doesn't that make you feel all empowered and stuff?
"STOP MAKING COOKIES!"
I promise I will, dear... After this batch.