01 -
Combine the milk, chopped Mexican chocolate, piloncillo, and cinnamon stick in a heavy saucepan. Warm over medium-low heat, whisking often, until the chocolate and piloncillo dissolve, about 8-10 minutes.
02 -
Whisk the warm water and masa harina in a medium bowl until completely smooth with no dry pockets.
03 -
Remove the cinnamon stick from the pot. Slowly pour in the masa slurry while whisking constantly so it blends into the chocolate base without lumps.
04 -
Bring to a gentle simmer, then reduce the heat to low. Cook for 15-20 minutes, whisking often and scraping the bottom, until the champurrado coats the back of a spoon.
05 -
Whisk in the vanilla and salt. Blend briefly with an immersion blender for a smoother texture if desired. Serve hot with a light dusting of ground cinnamon.