Preheat oven to 350 degrees F (180 degrees C).
Spray a 12-cup muffin tin and set aside.
Crack the Egg (2) and separate the egg whites from egg yolks. You will need 2 tablespoons of egg whites. Discard the egg yolks or save it for another recipe.
In a large bowl, using an electric mixer, beat together your Granulated Sugar (3 tablespoon), Egg (1) and egg whites.
Stir in your Banana (3), Unsweetened Apple Sauce (1/4 cup), and Vanilla Extract (1 teaspoon). Mix well.
Mix in All-Purpose Flour (1 1/4 cup), Unsweetened Cocoa Powder (1/2 cup), Baking Powder (1 teaspoon), and Baking Soda (1 teaspoon).
Fold in Mini Chocolate Chips (3 tablespoon).
Divide into 12 regular sized muffins. Bake in oven for 18 to 20 minutes.