It was a lazy Sunday afternoon and I was googling around for blueberry swirl cake—as you do—and I came across a lovely looking specimen on the blog the Kitchenist. What drew me to the recipe was the technique for adding the swirl: you make a blueberry syrup, mix it with some reserved batter from the cake, then dollop it on top of the pan. I liked how this gave the blueberry layer some structure and textural cohesiveness with the rest of the cake.
After thanking the wonder that is the internet, I simply stole the technique and applied it to a recipe for one of my favorite coffee cakes. I also upped the swirl to more of a marble because it's summer and I'm definitely going heavy handed on anything involving fruit. The crumb on the cake is very moist and light, with a good dose of vanilla to compliment the berries. But the vein of sweet berries is simply addictive, like the middle line of frosting in a slice of layer cake.
I like to make this cake in a tube pan and offer it one of two ways. I've served it warm at breakfast, purple and gold side up, and I've served it for dessert at a dinner party, with the berry layer hidden on the bottom. It's fun to watch people cut through the top and hit an unexpected layer of berries, especially when you reward their discovery with a scoop of vanilla ice cream.