Preheat oven to 375ºF.
Meanwhile, mix topping ingredients together until combined. Set aside.
Slice apples into 1/2" or 1/4” slices.
Add apples, blueberries, strawberries, and remaining filling ingredients in a baking dish. Stir to combine.
Cover evenly with topping. Bake until lightly browned and bubbly, about 30 Minutes.
Serve hot or cold.