1Combine flour, oats, sugar, baking powder, soda, and salt.
2In a large bowl, beat the egg lightly. Stir in the milk, oil, and vanilla. Add the mashed banana, and combine thoroughly. Stir the flour mixture into the banana mixture until just combined. Line a 12-cup muffin tin with paper bake cups, and divide the batter among them.
3Bake at 400 degrees F (205 degrees C) for 18 to 20 minutes.
Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.