1 cup long grain white rice
2 cups skinless almonds
1 inch cinnamon bark
8 cups water
1/2 cup sugar
1/4 teaspoon vanilla extract
Wash and drain the rice.
Using a spice grinder (an electric coffee grinder works well too), grind the rice until fine; combine with the almonds and cinnamon bark.
Add 3 1/2 cups water and let sit overnight, covered.
Blend rice mixture until smooth using a blender.
Add 2 1/2 cups of water and continue blending.
Add sugar and vanilla extract.
Strain horchata into a bowl first using a metal strainer and then a double layer of cheesecloth; finish with up to an additional 2 cups of water until it achieves a milky consistency.
Serve cold or over ice.