Grind rice in a blender until fine. Remove blender jar from the motor.
Add the almonds, cinnamon stick and hot water to the ground rice and stir with a spoon. Let the mixture cool completely, then cover and let it sit at room temperature for a minimum of three hours, ideally overnight. I keep everything in the blender jar to make things easier.
After soaking, add cold milk and sweetened condensed milk to the rice/almond/cinnamon mixture in the blender then blend until smooth. If you want your horchata sweeter, add more condensed milk, to taste.
Strain the milk mixture into a pitcher or jar. Refrigerate until ready to enjoy.
Fill a glass with ice fill half-way with cold brew (use more if you want a stronger drink).
Shake or stir horchata well before using.
Stir in the horchata, garnish with a cinnamon stick and enjoy.