Banana Cake With Peanut Butter Icing
["2 1/4 c. all-purpose flour", "1 1/4 tsp. baking powder", "1 tsp. baking soda", "1 tsp. salt", "1 c. mashed, very ripe bananas", "1 c. buttermilk", "2/3 c. butter", "1 1/2 c. sugar", "2 eggs", "1 tsp. vanilla"]
["Preheat oven to 350\u00b0.", "Grease and flour a 9 x 13-inch baking pan.", "In a medium bowl combine flour, baking powder, soda and salt.", "Set aside.", "In a small bowl combine bananas and buttermilk; set aside."]
["all-purpose", "baking powder", "baking soda", "salt", "bananas", "buttermilk", "butter", "sugar", "eggs", "vanilla"]