Bring 8 cups of water with cinnamon sticks to a boil; remove from heat, cover, and let steep for 1 hour.

Discard cinnamon sticks and return water to medium-low heat. Add Mexican chocolate stir until dissolved.

In a separate cup, dissolve corn starch in ¼ cup of cold water. Stir to prevent clumps and add to pot, stirring as you pour it in.

Add the milk and let it come to a slow boil, being careful to turn off heat as soon as it boils. It will thicken a little and will be creamier with whole milk.