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

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

Press remaining mixture onto bottom of ungreased 9x13 inch pan. Arrange apple slices over base. Blend sour cream and egg; spread evenly over apples. Sprinkle reserved topping mix over all. Bake at 350 degrees for 25-30 minutes or until topping is golden brown and bubbly. Serve warm. Refrigerate leftovers. Makes 12-15 squares.