In a bowl, measure out 2 cups of blackberries and 1 cup of sugar. Let stand for a minimum of 30 minutes.

Preheat the oven to 375 degrees.

In a small bowl, mix together gluten-free flour, baking powder, and salt.

Melt the butter in a microwave safe bowl. Stir into the flour mixture. Add the milk and mix thoroughly.

Spread the batter in an ungreased 8-inch x 8-inch pan or the equivalent size. Place a baking sheet under the pan. (I usually do this in case it bubbles over.)

Spoon the blackberry mixture over the top.

Bake 45 minutes until golden.

Serve warm with ice cream.