Preheat your oven to 350 degrees fahrenheit
Grease your muffin tin, or add your muffin liners
In a large bowl, combine mashed bananas, milk or yogurt, butter, eggs, sugar, and vanilla.
After combining, add in flour, baking soda, baking powder, salt and chocolate chips. Mix until all ingredients are mixed together.
Pour batter into muffin tin sections, and bake for 20-25 minutes.