1 Preheat oven to 325 degrees F (165 degrees C).
2 Beat egg whites until stiff but not dry.
3 Combine cream of tartar, baking powder, vanilla, cinnamon, oats, and mashed bananas.
4 In a separate bowl combine the flour, confectioner’s sugar, and salt.
5 Fold the banana mixture into the egg whites. Then fold the flour mixture into the egg white/banana mixture. Pour batter into one 9 or 10 inch round cake pan, coated with a non-stick cooking spray.
6 Bake at 325 degrees (165 degrees C) for 1 hour, until cake is firm and lightly golden. Cool for five minutes then slip out of pan onto a serving dish. Garnish with a light dusting of confectioner’s sugar.