In a large bowl, whisk together flour, sugar, baking powder, salt, and graham cracker crumbs until well combined.
Add whisked egg, melted butter, and milk into the flour mixture and mix until blended. Fold in chocolate chips.
Heat a griddle or pan at medium heat and spray lightly with cooking spray. Ladle about 3 tablespoons of batter onto the griddle for each pancake. Let pancakes cook until bubbles form before flipping and cooking until golden brown
Break chocolate bar up and put in a double broiler (or in a saucepan over another saucepan of boiling water) and stir it until melted.
To assemble: Spread about 2-3 Tbsp of marshmallow fluff on a pancake. Place a pancake on top and spread with another 2-3 Tbsp fluff. Repeat with a third pancake and then top with additional marshmallow fluff and melted chocolate.
Feel free to add garnishes like mini marshmallows, additional pips of chocolate, and graham cracker crumbs. Enjoy!