Give a quick rinse to the rice and then place it in a medium bowl.
Add the cinnamon stick and cover with the water. Mix a bit, then cover the bowl and allow it to sit overnight.
Next day, transfer the rice, cinnamon, and soaking water in a blender.
Blend for 3 minutes at high and set aside (read note 1).
In a medium pot pour the milk and add sugar. Heat it up over medium heat.
Pour into the pot the rice mixture, mix, and bring to a gentle simmer while stirring from time to time.
Keep the heat at medium-low and cook atole for 15 minutes while stirring constantly.
Taste and adjust with sugar if needed.
Turn off the heat and serve in mugs with a sprinkle of cinnamon powder on top.
Notes
If you don't want cinnamon bites in your drink, don't blend the cinnamon stick with the rice. You can add it to the pot with milk to infuse it instead.
Make it creamier by adding 1 can of evaporated milk.
You can also add more flavors and aromas to this rice atole, think of orange peel, star anise, or whole cloves.
For a dairy-free drink, replace whole milk with your favorite plant-based milk such as almond milk, coconut, milk, soy milk, etc.