8Preheat your oven to 350°F (175°C) and line a muffin tin with paper liners.
In a large bowl, mash the bananas until smooth.
Peel and finely chop the apple, then add it to the mashed bananas.
Melt the butter and add it to the banana-apple mixture along with the sugar, milk, and vanilla. Mix well.
In a separate bowl, combine the flour and baking powder.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined.
Spoon the batter into the prepared muffin tin, filling each cup about 2/3 full.
Bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow the muffins to cool in the tin for 5 minutes before transferring them to a wire rack to cool completely.
Enjoy your Banana Apple Muffins!