In a medium bowl, combine the flour, sugar, baking powder and salt and stir with a fork to blend
In a mixing bowl, combine the mashed bananas, egg, melted butter, applesauce, sour cream, vanilla extract and milk. Beat on medium until well blended. Reduce the speed to low and blend in dry ingredients (do not overmix). Stir in the chocolate chips
Fill each muffin cup with 1 level tablespoon of batter. Bake the muffins for about 15-20 minutes or until the tops are golden and a toothpick comes out with some melted chocolate, but no crumbs.
Transfer the muffins to a rack to cool. Repeat with the remaining batter