Prepare the Base:
Line a baking sheet with wax paper and grease with cooking spray.
In a pot over low heat, melt the butter. Add mini marshmallows and stir until melted.
Remove from heat and stir in Rice Krispies cereal until well coated

Add Toppings:
Spread marshmallow Fluff over the cereal base.
Sprinkle crushed graham crackers over the Fluff, pressing them slightly.
Pour melted chocolate over the graham crackers, smoothing with a spatula

Roll and Chill:
Cut the layered sheet in half lengthwise.
Roll up each half from the long side, like sushi rolls

Serve:
Slice into sushi roll pieces.
Serve with additional melted chocolate for dipping