Ingredients
1 1/2 cups all-purpose flour
2 teaspoons baking powder
1/2 teaspoon coarse salt
4 ounces (1 stick) cold unsalted butter, cut into small pieces
3/4 cup cold heavy cream, plus more for brushing
1/4 teaspoon ground cinnamon
1/2 cup granulated sugar, plus more if needed
3 tablespoons cornstarch, plus more if needed
6 cups (3 pints) blackberries or raspberries
Sanding sugar, for sprinkling
Vanilla ice cream, for serving (optional)
Preparation
Preheat oven to 375 degrees. Pulse flour, baking powder, and salt in a food processor (or whisk together by hand in a large bowl) until combined. Add butter and process (or cut in using a pastry blender or two forks) until mixture resembles coarse meal. Transfer mixture to a large bowl, if needed, and add heavy cream in a slow, steady stream, mixing with a wooden spoon until dough just comes together. Pat dough into a square on work surface and cut into 9 equal squares.
Whisk together cinnamon, granulated sugar, and cornstarch in a bowl. Add berries; toss gently to coat. Transfer mixture to an 8-inch square baking dish. Top berries with dough squares, spacing evenly. Brush dough with heavy cream and sprinkle with sanding sugar. To catch any juices that may bubble over when baking, place the baking dish on a rimmed baking sheet lined with parchment paper and fitted with a wire rack or lay a piece of foil on the rack below the cobbler. Bake until berries are bubbling in center and biscuits are golden brown, 50 to 75 minutes. If biscuits are browning too quickly, tent with foil. Transfer dish to a wire rack and let cool slightly, about 30 minutes. Serve with ice cream if desired.
