Preheat oven to 350 F and line muffin tin with muffin cups (makes 12)
Mix together bananas, milk, melted butter, egg and vanilla in a large bowl until well combined (should be smooth)
In a small bowl whisk together flour, sugars, baking powder, and salt, add to wet ingredients and stir to combine.
Stir in chocolate chips and chopped walnuts, do not over mix your batter or you will have dense muffins.
Fill 12 muffin cups (you want to fill with batter almost right to the top so you get a nice round muffin top with a slight crunch!)
Bake 30 minutes, or until a toothpick inserted in middle comes out clean.
Allow to cool and enjoy