Banana Snack Cake
["1 c. butter or margarine", "1 c. sugar", "2 eggs", "2 ripe mashed bananas", "1/2 c. buttermilk*", "1 1/2 tsp. baking soda", "1/2 tsp. salt", "1 tsp. vanilla", "1 c. oats", "1 1/2 c. all-purpose flour", "1/2 c. whole wheat flour", "1 c. chocolate chips"]
["Preheat oven to 350\u00b0.", "Grease a 9 x 13-inch pan."]
["butter", "sugar", "eggs", "bananas", "buttermilk", "baking soda", "salt", "vanilla", "oats", "flour", "whole wheat flour", "chocolate chips"]