1. Preheat oven to 400°F. Grease the bottom and sides of a glass 13 x 9 inch pan. Cream together butter and sugar. Add eggs and vanilla; beat until smooth. Add flour, baking powder, baking soda, salt and sour cream. Mix well.
2. Layer in a 9 x 13 inch pan, beginning with cake mix. Add a layer of topping, then cake mix and then topping.