Place berries in a medium bowl. In another medium bowl, combine flour and sugar. Remove 3 tablespoons of flour mixture and gently toss with berries. Place berries in an 8-inch square pan.
To make topping, add melted butter to remaining flour mixture; combine well. Crumble little bits of topping all over top of berries. Bake until berries just start to bubble, about 35 to 40 minutes. Cut into 8 pieces; serve warm or at room temperature. Yields 1 piece per serving.