Directions

1. Preheat oven to 350°F. In a medium bowl combine cake mix and butter until mixture resembles coarse crumbs. Reserve 2/3 cup crumb mixture; set aside. Press remaining crumb mixture into bottom of a 13x9x2-inch baking pan.
2. Arrange apple slices evenly on top of crumb mixture in prepared pan; set aside. In a small bowl stir together egg and sour cream until smooth. Spread over apple slices.
3. In another medium bowl stir combine reserved crumb mixture, brown sugar and cinnamon. Sprinkle on top of sour cream mixture in baking pan. Bake, uncovered, 25 to 30 minutes or until center is set and apples are tender. Cool slightly. Cut into bars, and serve.