When we think of what to do with blackberries, custards aren't typically what comes to mind. Jam? Sure. Cobbler? You bet. But a pudding or ice cream? Not so much.
It makes sense, in a way. Blackberries are juicy, explode-y things full of seeds that get in the way of the pale creamy swirls of custard. Blackberries are all summer mess. Custards, however humble, feel somehow refined.
The exception to this is a blackberry swirl, used in cream pies, cheesecakes, and—to great effect—ice cream. I want my explode-y, jammy mess of fruit right now, but it's also a bajillion degrees outside, and I want my ice cream too. So here's this recipe, which is at once a fresh breath of summer breeze and also a rich, frosty, custardy scoop.
The base is steeped with generous amounts of lemon peel and minced ginger, mild enough to keep the blackberry the star, but assertive enough to add some citrus brightness and a slight spicy bite. Don't bother zesting the lemons; just peel off the yellow skin with a vegetable peeler, making sure to leave the white pith behind. The larger chunks will be easier to strain out.
Turning 3 1/2 cups of blackberries into a dark, intense 1/2 cup of swirl isn't difficult at all, but requires some care. Purée your blackberries just enough to loosen the juice; it'll be easier to strain out the larger chunks of pulp and seeds. And save adding sugar to the syrup until the very end. With this much of a reduction, it's easy to burn all that sugar. Even careful heat management can introduce more caramelized, less fruity flavors than you'd like for this application.
Making the actual swirl is even easier. Just don't think swirl—think layers. Spoon your churned ice cream into a container in thirds, and add the syrup in equal amounts between the layers. The motion of your scoop will be enough to create that pretty swirl effect.