Preheat oven to 375 degrees F.
In a large bowl, combine flour, oats, baking powder, baking soda, salt and brown sugar and set aside.
In a food processor (or blender or mixer) combine yogurt, bananas, melted butter, peanut butter, milk, egg and vanilla until very well blended. Mixture will be fairly thick.
Combine wet and dry ingredients, as well as chocolate chips, and stir until well combined but do not over mix.
Scoop into a greased muffin tin.
Bake for approx 18-22 minutes or until toothpick inserted in center comes out clean and/or top of muffin springs back when lightly touched. Enjoy! These freeze well and make for a great breakfast or quick snack.