Sour Cream Banana Bread

1/3 cup butter
2 cup sugar
3 eggs
1 1/2 tsp vanilla
3 cups flour
1 1/2 tsp baking powder
1 ½ tsp baking soda
1 tsp salt
4 mashed bananas
1 ½ cup sour cream

Cream together butter and sugar. Beat in eggs. Add vanilla. Add flour, baking powder, baking soda, and salt. Alternate this with the sour cream. Add bananas and mix until blended. Bake in small loaf pans in 350 degree oven 40 minutes