Chocolate Chip Banana Nut Muffins   Author: Angie Serves: 28 mini muffins Ingredients 2 sticks (1 cup) butter, softened 3/4 cup sugar 2 large eggs 1 teaspoon vanilla 1/2 cup buttermilk 1 cup mashed very ripe bananas 2 cups all-purpose flour 1 cup quick-cooking rolled oats 1 1/2 teaspoons baking soda 1/2 teaspoon salt