Preheat your oven to 350°F (175°C). Grease a muffin tin or line with muffin liners.
In a large mixing bowl, combine the mashed bananas, milk, honey, and beaten egg. Mix well.
In another bowl, whisk together the oats, whole wheat flour, baking powder, baking soda, cinnamon, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Divide the batter evenly among the muffin cups.
Bake for 20 minutes, or until a toothpick inserted into the center comes out clean.
Let the muffins cool in the tin for a few minutes, then transfer to a wire rack to cool completely.