Simmer 1 cup milk, 2 cups water and 1 cinnamon stick. Whisk 1/2 cup of the liquid with 1/4 cup masa corn flour in a bowl; whisk back into the milk. Add 3 ounces chopped bittersweet chocolate and 3 tablespoons dark brown sugar; whisk until thick. Discard cinnamon and puree.
Photographs by Marko Metzinger/Studio D