Horchata is a sweet Mexican rice milk made by blending rice, water and cinnamon, then allowing the mixture to stand at room temperature for anywhere from three hours to overnight. There are many variations on the basic recipe, but most call for these basic ingredients plus sugar or honey.
To make an easy version of horchata, combine 1 cup of rice and 1 cinnamon stick with 4 cups of water in a blender. Pulse to grind the rice coarsely, then pour the mixture into a large bowl, and add 4 more cups of water. Let this mixture soak at room temperature for at least three hours.
Puree the mixture in the blender until it is smooth, then strain it into a pitcher through cheesecloth or a fine sieve to remove any remaining rice or cinnamon particles. Stir in 1/2 cup of sugar, then chill the mixture. before serving it over ice.
A more complicated recipe might call for extra spices or flavorings, such as cloves, vanilla or star anise, and it might finish the horchata with either whole milk or coconut milk. Another option is to use sweeteners other than white sugar, such as honey, to make the horchata slightly less sweet.