Preheat oven to 350 degrees
Cut butter into dry cake mix until crumbly
Pat mixture lightly into ungreased 13" x 9" x 2" pan, building up slightly at edges
Bake 10 minutes
Arrange apple slices on warm crust
Sprinkle cinnamon on apples
Blend sour cream and egg yolks and drizzle over apples
Bake 25 minutes or until apples are lightly browned
Serve warm with a scoop of vanilla ice cream
Yield: Servings determined by package of cake mix