Rinse 1 cup long-grain white rice
Soak the rice with 2 cups water, 1 cinnamon stick, and 1/2 cup almonds for 4 to 8 hours
Blend the soaked rice mixture until smooth
Strain the blended mixture through a fine sieve or cheesecloth
Add 2 to 3 cups cold water to the strained liquid
Stir in 1/2 cup milk or evaporated milk
Add 1/4 to 1/2 cup sugar to taste
Add 1 teaspoon vanilla extract
Chill the horchata in the refrigerator
Serve over ice
Sprinkle with ground cinnamon if desired