Preheat oven to 400 degrees. Grease a 9x9 baking dish (11x7 works fine as well) with cooking spray.
Mix apples and berries into a large bowl. Add brown sugar, white sugar, cornstarch, cinnamon and all spice together to the fruit and mix until well combined. Set aside.
In a separate bowl, with a pastry cutter or fork, combine butter, muffin mix, and brown sugar until well combined (it will take a few minutes to work the butter into the mix).
Pour fruit in an even layer in the baking dish. Top with spoonfuls of the muffin mix (the topping does not need to cover all of the fruit). Sprinkle with cinnamon sugar.
Bake for 40-45 minutes, or until the fruit is bubbling and the muffin mix is golden brown and set.
Serve with whipped cream, fresh berries, and/or ice cream!
Enjoy!