Pre-heat the oven to 325 F. Grease and flour a bread pan.
Instructions:
Place the butter and sugar in a mixer. Cream until smooth. Add the eggs - one at a time with the mixer running. In a separate bowl, sift together the flour and baking powder. Blend well into the mixture. Add the sour cream and vanilla and mix until blended. Pour the batter in the loaf pan. Bake for 55-60 minutes. Allow to cool before serving.