Add the milk, cream, and sugar to a small saucepan over low heat. Heat until hot, stirring constantly but do not allow the mixture to boil.
Add the chocolate to the mixture and mix until completely blended and smooth. Bring to a gentle simmer and keep simmering for about 1 minute, then turn off the heat and serve. For a thicker drink, simmer for 1 more minute. If it gets too thick, add a splash of room temperature milk and mix over low heat until combined.
Notes
Storing Instructions: Store any leftover hot chocolate covered in the refrigerator for 1-2 days. Reheat on the stovetop on low heat until hot again, making sure to stir constantly.