I discovered Mexican chocolate many years ago and fell in love. Mexican chocolate is made from dark, bitter chocolate mixed with sugar and cinnamon.
The chocolate usually comes in hexagonal tablets that can be split into equal wedges and then melted into milk. The drink can also be mixed with spirits such as Kahlúa. Several brands you might find in the Latin section of your local grocery store might include: Abuelita, Ibarra and Moctezuma.
I simmer 4 cups of milk and one whole disk of chocolate together in a sauce pan. Stir continuously with a whisk or molinillo (a whisk-like wooden stirring spoon native to Meso America) until melted and frothy or creamy.