Chop your chocolate into small pieces and combine it with the milk in a small saucepot over medium heat.
Whisk continuously and allow the milk to reach a scalding temperature (about 180 degrees Fahrenheit, with bubbles on the side). Remove from the heat and continue to stir until the chocolate is completely melted.
Pour into a mug and top with marshmallows and some grated chocolate. Enjoy!
Notes
Measure out your milk by using the mug you will be serving it in.