In a mixing bowl, cream butter and sugar.
Add eggs, sour cream and vanilla; mix well.
Combine flour, baking powder, baking soda and salt; add to creamed mixture and beat until combined.
Pour half the batter into a greased 13-in. x 9-in. baking pan.
Combine topping ingredients; sprinkle half of topping over batter.
Add remaining batter and topping.
Bake at 325 degrees F for 40 minutes or until done.· 40m