Preheat oven to 375F. Spray a 9x13" pan with non stick spray and set aside.
Pour frozen berries into a bowl with sugar, toss to coat. Pour into your baking dish and spread out evenly.
In another bowl combine cake mix with melted butter and stir together to create a batter. Pour this evenly on top of the frozen fruit, spread out evenly.
Bake uncovered for 70-80 minutes or until the top is golden brown. Allow to cool for 10 minutes in the pan. Scoop out with a spoon and serve with a scoop of ice cream on top!