Fresh Berry Gratin

From America's Test Kitchen Season 1: Crisps, Cobblers, and Gratins

Quicker than a crisp and dressier than a shortcake, a gratin is a layer of fresh fruit piled into a shallow baking dish, dressed up with bread crumbs, and run under a broiler. The topping browns and the fruit is warmed just enough to release a bit of juice. We wanted to find the quickest, easiest route to this pleasing dessert. We started with perfect raspberries: ripe, dry, unbruised, and clean. Tossing the sweet-tart berries with just a bit of sugar and kirsch (a clear cherry brandy; vanilla extract can be substituted) provided enough additional flavor and sweetness. For the topping, we combined soft white bread, brown sugar, cinnamon, and butter in the food processor and topped the berries with the fluffy crumbs. Instead of broiling the gratin, which can produce a crust that’s burnt in spots, we simply baked it. We found that a moderately hot oven gave the berries more time to soften and browned the crust more evenly.?Why This Recipe Works: Gratins can be very humble, as in our Simple Raspberry Gratin (page 544), where the topping is little more than sweetened bread crumbs. Or they can be a bit more sophisticated, as when they are topped with the foamy Italian custard called zabaglione. Zabaglione is made with just three simple ingredients—egg yolks, sugar, and alcohol—but it requires constant watching so that the mixture doesn’t overcook. It also needs to be whisked just long enough to transform the egg yolks to the ideal thick, creamy texture. We were after a foolproof method for this topping for a gratin that could serve as an elegant finale to a special summer meal. We chose to make individual gratins—perfect for entertaining—and settled on raspberries, strawberries, blueberries, and blackberries. We tossed the berries with sugar and a pinch of salt to draw out their juices and let the mixture sit while we worked on the custard. To prevent scrambled eggs, we kept the heat low; for the right texture, we didn’t stop whisking when soft peaks formed—instead we waited until the custard became slightly thicker. As for flavor, tasters thought that zabaglione made with the traditional Marsala wine was a bit sweet and cloying on top of the berries. We switched to a crisp, dry Sauvignon Blanc and found that its clean flavor allowed the berries to shine. However, with that change, our zabaglione was almost runny. After trying to thicken it with cornstarch and gelatin (with disappointing results), we turned to whipped cream. After carefully folding a few tablespoons of whipped cream into the cooked and slightly cooled zabaglione base, we spooned it over the berries. Finally, we sprinkled the custard with a mixture of brown and white sugar before broiling for a crackly, caramelized crust.