Preheat oven to 375F. Grease the muffin pan with melted butter.
Unroll the crescent dough and place a single triangle piece into each muffin tin cup. Use your fingers to form the cup and smash the dough into place.
Bake for seven minutes.
Remove the muffin tin from the oven and let it cool for about two minutes.
Place one tablespoon of Nutella in the center of each cup.
Cover with the mini marshmallows.
Bake until the marshmallows have browned to your desired shade. This should take 5-7 minutes (unless you like the REALLY toasty!)
Don't put too much crescent dough on the bottom of the pan. This will allows it to bake more evenly. Push more dough on the sides.Add your favorite additions like Hershey bars, peanut butter, cut strawberries, or peanut butter chips. Sometimes, the crescent rolls will close up as they bake. If this happens, it's not a big deal. Just take a spoon and open them back up to add in the Nutella.Don't over-bake the cups or they will turn out too dry and may break apart.Reheat by microwaving for 10-15 seconds.