Heat oven to 350 degrees F.
In large bowl, toss apples and 1 teaspoon cinnamon. Spread apples evenly in ungreased 13x9-inch pan. In large bowl, mix cake mix and nuts. With pastry blender or fork, cut in butter until crumbly. Add 1 teaspoon cinnamon and the egg; mix well.
Sprinkle evenly over apples. Bake about 45 minutes or until topping is light brown. Serve warm with ice cream.
Always read labels to make sure each ingredient is gluten free. Products and ingredient sources can change. To help keep the crispy topping intact, use a wide spatula to remove the dessert from the pan.