Rinse the rice under cold water until the water runs clear.

Place the rinsed rice in a bowl and add 2 cups of water. Soak at room temperature for at least 4 hours or overnight.

Drain the soaked rice and add it to a blender with the remaining 2 cups of water. Blend until smooth, about 1–2 minutes.

Strain the blended mixture through a fine-mesh strainer or cheesecloth into a large bowl to remove solids.

Add the almond milk, sugar, ground cinnamon, vanilla extract, and a pinch of salt to the strained liquid. Stir until the sugar is completely dissolved.

Cover the bowl and refrigerate the horchata for at least 30 minutes to chill and enhance flavors.

Serve the chilled horchata over ice in glasses.

Garnish with a sprinkle of ground cinnamon on top if desired.