Chocolate Sour Cream Pound Cake

1.  Preheat the oven to 325 degrees F. Greaseand flour a 10-inch tube pan. 
2.  Using an electric mixer, cream together the butter, sour cream, and sugar. Add the eggs, 2 at a time, beating well after each addition. Add the vanilla.
3.  In another bowl, stir together the flour, baking powder, and cocoa. Add 1/2 the flour mixture to the creamed mixture, beat well, add the remaining 1/2 flour mixture, and continue to beat at medium speed for 2 minutes. 4.
4. Pour the batterinto the prepared pan and bake for 1 hour 15 minutes. Continue to bake for an additional 15 minutes if necessary, but do not open the oven to check the cakefor at least 1 hour.