Separate crescent rolls into individual triangles.
In a small bowl, mix together cinnamon and sugar.
Place marshmallow into the center of a dough triangle. Carefully wrap the dough around the marshmallow. Pinch the seams together tightly to seal in marshmallow. This is very important.
Dip the roll into melted butter, then roll in sugar mixture.
Place on a baking sheet.
Bake in a preheated oven 15 minutes or until golden brown.