Preheat oven to 350 degrees F. Mix the topping ingredients in a bowl until the butter is thoroughly incorporated and the mixture is the consistency of fine meal. Set aside. In another bowl, toss the sugar, flour, and cinnamon with the chopped apples. Place the apple mixture in a greased 9x13-inch baking pan and cover with the topping. Bake until golden brown, about 30 minutes.
Variation: Substitute blueberries for half the apples.