Heat oven to 350°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.