Filling:
8 cups blackberries (or a mix of berries)
⅓ cup sugar
2 tablespoons cornstarch
2 teaspoons lemon juice
Biscuit crust:
2 cups flour,½ cup sugar1½ teaspoons baking powder¼ teaspoon baking soda½ teaspoon salt½ cup cold unsalted butter, cut into pea-size pieces or grated½ cup buttermilk