Nonstick cooking spray
3 pounds fresh berries (blackberries, blueberries, strawberries, raspberries, or a mix)
Zest and juice of 1 lemon
2 teaspoons cornstarch
½ teaspoon vanilla extract
1/3 cup granulated sugar
2 cups all-purpose flour
3/4 cup confectioners sugar
1 tablespoon baking powder
1 teaspoon salt
½ cup (1 stick) cold, unsalted butter, cut into small pieces
1 cup half-and-half
Preheat the oven to 350º Fahrenheit. Coat a 9-by-13-inch baking pan with cooking spray.
Place the berries in a medium bowl. Add the lemon zest and juice, cornstarch, vanilla, and granulated sugar and toss to combine. Transfer the mixture to the prepared baking pan and spread out into an even layer.
To make the topping mixture, in a large mixing bowl, combine the flour, confectioners sugar, baking powder, and salt. Cut in the butter with a pastry cutter or two knives until the mixture resembles coarse meal (alternatively, you can combine the flour, confectioners sugar, baking powder, salt, and butter in a food processor and pulse until the mixture resembles coarse meal.) Stir in the half-and-half.
Dollop the batter on top of the berries in the baking pan.
Bake for about 1 hour, until the top turns golden brown and the berry filling bubbles.