Rinse 1 cup long-grain white rice under cold water until the rinse runs mostly clear. Place the rinsed rice in a bowl with 2 cups of water and the 2 whole cinnamon sticks. Cover and let soak at room temperature for at least 3 hours, or up to overnight in the refrigerator for a more developed flavor.

Blend soaked rice

After soaking, pour the rice, the soaking water (including cinnamon sticks), and 2 cups fresh water into a blender. Blend on high until the rice is very broken down and the mixture is milky, about 1 to 2 minutes. Stop and scrape sides if needed. The mixture will be grainy — this is expected.

Strain & Sweeten

Strain the milk

Place a fine-mesh sieve lined with a double layer of cheesecloth (or a very fine sieve) over a large pitcher or bowl. Pour the blended rice mixture through the cloth/sieve, pressing on the solids with the back of a spoon to extract as much liquid as possible. Discard the solids left in the cloth (or save for another use).

Combine remaining liquid

To the strained rice liquid, add 1 cup whole milk (or the remaining 2 cups if you prefer creamier — this recipe uses 2 cups total), 3 tablespoons granulated sugar, 1 teaspoon ground cinnamon, and 1 teaspoon vanilla extract. Whisk until sugar is dissolved. Taste and adjust sweetness or creaminess: add up to 2 tablespoons sweetened condensed milk for extra sweetness/creaminess, or more milk/water to thin.

Chill & Serve

Chill the horchata in the refrigerator for at least 1 hour before serving. Chilling lets flavors meld and the beverage to cool. If you soaked overnight, chilling 30 minutes is sufficient.

When ready to serve, stir the horchata, fill glasses with ice cubes, and pour horchata over ice. Optionally add a few drops of almond extract for a different note (start with 1/4 tsp), and dust each glass with a light sprinkle of ground cinnamon.

Store any leftover horchata in a sealed container in the refrigerator for up to 3 days. Shake or stir before serving, as separation may occur.