Preheat oven to 350 degrees.
Cream butter and sugar. Mix in eggs, vanilla, and sour cream. Sift flour, baking powder, and salt; add to above mixture.
Put half of batter in a greased and floured pan (bundt, angel food, or 9 X 12 inch).
Sprinkle the nut mixture on top of the batter in the pan. Spread remaining batter over nut mixture in the pan. Bake for one hour.