Preheat the oven to 350 degrees. Fill muffins cups with liners.

In a medium bowl, combine the flour, baking powder, cinnamon and salt.

In a large mixing bowl, cream together the butter and sugar. Add the egg whites, one at a time with beating after each one, and vanilla. Mix well.

Add in the flour mixture, alternating the flour and the mashed banana, beginning and ending with the flour mixture.

Add in the ¼ cup mini chocolate chips.

Divide the batter evenly into each muffin cup, filling about half way. Sprinkle the extra tablespoon of mini chocolate chips on top of each muffin.

Bake at 350 degrees for 17-20 minutes. Let them sit in the muffin pan for five minutes. Then place on a wire rack until completely cooled.