Banana Bread Bars with Brown Butter Frosting Ingredients Banana Bread Bars: 1-1/2 c. sugar 1 c. sour cream 1/2 c. butter, softened 2 eggs 1-3/4 (3 or 4) ripe bananas, mashed 2 tsp. vanilla extract 2 c. all purpose flour 1 tsp. baking soda 3/4 tsp. salt 1/2 c. chopped walnuts (optional) Brown Butter Frosting: