Preheat your oven to 375°F (190°C) and line a muffin tin with paper liners.
In a large mixing bowl, combine the oats, mashed bananas, milk, egg, honey, baking powder, vanilla extract, and salt. Mix well until all ingredients are combined.
Divide the batter evenly among the muffin cups, filling each about ¾ full.
Bake in the preheated oven for 20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the tin for a few minutes, then transfer to a wire rack to cool completely.