Preheat the oven to 350F, and spray a regular size loaf pan with some nonstick cooking spray.
In a bowl, whisk together the egg, egg whites, and brown sugar and mix well.
Mix in the mashed banana, apple sauce, and vanilla extract.
Next, stir in the all purpose flour, cocoa powder, baking powder, baking soda, and crushed graham crumbs. Leave 1 tablespoon of crushed graham crackers aside for topping.
Mix well then fold in the chocolate chips. Pour the batter out into the loaf pan.
Bake the loaf in the oven for 45 minutes.
Let it cool for 30 minutes then remove the loaf from the tin.
Melt the marshmallow fluff in the microwave for approx 30 seconds - it will rise some. Spread it quickly over the loaf, then melt the chocolate in a small dish in 35 second intervals, stirring each time until the chocolate is fully melted. Drizzle the chocolate over the loaf then sprinkle the remaining graham cracker crumbs over the top.
Cut the loaf into 10 equal pieces. Enjoy!