Fiesta Banana Cake

2 C flour
1 t baking soda
1 t baking powder
3/4 t salt
1 1/3 C sugar
1/2 C margarine or butter
1/2 C sour milk or buttermilk
1 t vanilla
1 C mashed bananas
2 eggs
walnuts

Stir butter to soften. Stir in dry ingredients. Add 1/4 C sour milk, vanilla and bananas. Mix. Beat 2 min. Add eggs, nuts and remainder milk. Beat 1 min. Bake at 375 for 25-45 min.