In a large bowl, cream together the butter and sugar. Beat in the eggs, one at a time, mixing well after each. Then stir in the vanilla. Combine the flour, baking soda and baking powder, add to the creamed mixture and mix until all of the flour is absorbed. Finally, stir in the sour cream. Mix for 1 or 2 minutes just to be sure there are no lumps. Pour the batter into the prepared pan.