Note: For this recipe, you will need a fine sieve, cheesecloth, or both.
In skillet, toast rice and one of the cinnamon sticks over high heat. Toss regularly to avoid burning. Rice is ready when toasty in color and smells rich and nutty. Remove cinnamon stick and set aside. Let rice cool. Place rice in a blender or food processor and blend on medium to break grain.
Place broken grains in a plastic storage container. Add toasted cinnamon stick, fresh cinnamon stick, and milk. Cover and refrigerate for 24 hours (or longer).
Remove from fridge. Using fine sieve or cheesecloth (we use both, one after the other, for a creamy texture), strain seasoned milk away from rice. Discard rice.
Stir in sugar to taste. Stir in spirit, again to taste. Add extra spices if desired.
Bottle and refrigerate (the rum fortifies, so it will keep for months on end, becoming richer over time), or warm on stovetop* and serve hot.
*Most alcohol boils around 172 degrees, and milk scalds slightly below that, so be careful not to burn the milk or boil off the booze.