Add the cornstarch to the milk and whisk it together until there are no more lumps.
Next add the milk, heavy cream, and cocoa powder to a pot heated over medium low heat.
Stir constantly so a skin doesn't form on top of the milk. You can add in any additional spices at this time.
Once you start to see steam rising and little bubbles forming on the sides of the pot, remove the pot from the heat.
Do not let this boil as the milk will curdle and the hot chocolate will get grainy.
Add the chopped chocolate and vanilla to the pot and stir constantly until the chocolate completely melts through.
It will look grainy in the beginning but it will become smooth and silky.
Add sugar to taste. You may not need additional sugar.
Serve immediately and add your toppings.
