Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.
In a mixing bowl, mash the ripe bananas until smooth.
Add the rolled oats, flour, milk, honey or maple syrup, and oil to the bananas.
Crack in the egg and mix until well combined.
In a separate bowl, whisk together the baking powder, baking soda, cinnamon, and salt.
Gradually add the dry ingredients to the wet mixture, stirring gently.
Spoon the batter evenly into the prepared muffin tins.
Bake for 20-25 minutes or until a toothpick inserted comes out clean.
Let the muffins cool in the tin for a few minutes before transferring to a wire rack.