- 2 cups fresh blackberries, or more to taste
- 2 cups white sugar, divided
- 1/2 cup butter
- 3/4 cup milk
- 3/4 cup all-purpose flour
- 2 teaspoons baking powder
- 1/4 teaspoon salt
- Preheat oven to 325 degrees F (165 degrees C).
- Mix blackberries and 1 cup sugar together in a bowl; let stand until mixture becomes juicy, 5 to 10 minutes.
- Place butter in a 9×13-inch baking dish and put dish in the preheating oven until butter is melted, 2 to 5 minutes. Remove dish from oven.
- Combine remaining 1 cup sugar, milk, flour, baking powder, and salt in a large bowl until batter is smooth; pour over melted butter. Do not stir. Spoon blackberry mixture over batter.
- Bake in the preheated oven until bubbling and cooked through, about 1 hour.