- 6 cups fresh blackberries
- 2 teaspoons lemon juice
- 1 cup white sugar
- 2 teaspoons cornstarch
- 1/4 cup cold butter, cubed
- 4 cups all-purpose flour
- 1/4 cup white sugar
- 1 teaspoon ground cinnamon
- 1 tablespoon salt
- 1 tablespoon baking powder
- 2 teaspoons baking soda
- 1 cup chilled butter, diced
- 1 1/3 cups buttermilk, plus additional for brushing
- 1/4 cup white sugar
- Preheat an oven to 375 degrees F (190 degrees C). Butter a 9×13-inch baking dish.
- Place the blackberries in a mixing bowl, and sprinkle with lemon juice. Toss with 1 cup sugar and cornstarch until evenly coated. Place into the prepared baking dish, and arrange the cubes of butter on top. In a large bowl, whisk the flour, 1/4 cup sugar, cinnamon, salt, baking powder, and baking soda together. Cut in 1 cup of chilled, diced butter using a pastry cutter until the butter is in pieces no larger than a pea. Stir in the buttermilk until a batter has formed. Spoon the batter evenly over the blackberries. Brush the top of the batter with additional buttermilk to moisten, then sprinkle with the remaining 1/4 cup of sugar.
- Bake in the preheated oven until the the fruit is tender, and the biscuit top is golden, about 25 minutes.