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

Preheat oven to 350 degrees. Combine first two ingredients. Mix until crumbly. Reserve 2/3 cup for topping. Mix well, set aside. Press remaining mixture onto bottom of ungreased 12 x 9 inch pan. Arrange apple slices over mixture in pan. Blend sour cream and egg and spread evenly over apples. Sprinkle reserved topping mixture over all. Bake at 350 degrees for 30 minutes or until golden brown and bubbly. Serve warm. Refrigerate leftovers.