Step 1Heat 2 cups of water and the cinnamon sticks together in a saucepan over medium heat until the sticks are soft, 10 minutes; when the water comes to a boil, stir in the chocolate, then stir into the cinnamon liquid.
Step 2Whisk the masa flour into 1 cup of water, making sure it is free of lumps. Add the masa mixture to the chocolate mixture. Whisk well until the chocolate has dissolved.
Step 3Add the evaporated milk and whole milk and whisk to combine. Stir until the masa, chocolate and milk are thoroughly combined and the liquid is thick. Add additional water if needed.
Step 4Remove the cinnamon sticks and serve in small cups. (Note: Champurrado will thicken as it cools. Thin with additional water and reheat to serve.)