1 pkg. yellow cake mix
1/2 c. soft butter
1/4 c. firmly packed brown sugar
1/2 tsp. cinnamon
3 apples, thinly sliced
1 c. sour cream
1 egg

Preheat oven to 350 degrees. Combine cake mix and butter until crumbly. Reserve 2/3 cup for topping. Add brown sugar and cinnamon. Mix well. Set aside.

Press remaining crumbs onto bottom of ungreased 9 x 13 inch pan. Arrange apple slices over base. Blend sour cream and egg, spread evenly over apples. Sprinkle with reserved crumbs. Bake at 350 degrees for 25 to 30 minutes.