This recipe works with stone fruit too.
Preheat oven to 350. Spray pie pan with non-stick (or butter).
In a medium bowl, whisk sugar and flour together. Add milk and whisk together. Add melted butter and whisk together.
Rinse and pat blackberries dry. Pour batter into pie pan, sprinkle blackberries evenly over the top of the batter. Bake for 1 hour until brown on top.