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

Preheat oven to 350 degrees. Combine first 2 ingredients; mix until crumbly. Reserve 2/3 cup for topping. Add brown sugar and cinnamon to reserved topping mixture. Press remaining mixture into the bottom of an ungreased 9 x 13 inch pan. Arrange apple slices over base. Blend sour cream and egg. Spread over apples. Sprinkle with topping over all. Bake at 350 degrees for 25-30 minutes until topping is golden and bubbly.