Since I had no idea what it had in it, even after drinking it, I did some research. Wait... all it has in it is rice, water, sugar, milk, cinnamon and vanilla? That didn't seem possible. I did some more research, read some recipe reviews and came up with my own method. It has lots of possibilities and flexibility depending on your taste. I'm sure I'll come up with my own favorite combinations over time.
But for now, here's my base recipe for horchata...
1 1/2 cups rice
2 cups water
Place in a blender and pulse 6-7 times.
Add 3 more cups of water.
Blend until the rice is coarsely ground.
Add 2-3 whole cinnamon sticks.
Put a cover on it and place in fridge for 6-8 hours or overnight.
Remove from fridge and pour through a sieve into a clean bowl or pitcher.
Place 1/2 cup sugar (use more or less to taste) and 1/2 Tablespoon of cinnamon into a food processor and pulse until the sugar is finely ground. This helps it dissolve better in the cold liquid.
Whisk well into the rice-y liquid until dissolved.
Then pour in 1 to 1 1/2 cups of milk. I like mine richer so I used some milk with heavy cream added. But I think you could also use half and half or a can of evaporated milk. You could also used any non-dairy milks. (I'm going to try all of those ideas someday)
Then gently whisk in 1/2 Tablespoon of vanilla. I also threw in a bit of almond extract. It's not authentic but I love the flavor it gives. That being said, I will probably try vanilla almond milk next.
Chill and serve. Shake well before serving. It will settle a bit.
By the way, I was right. It is good iced with coffee! Mmmm!