Step 1In a small saucepan, bring 3 cups water to a boil. Add the piloncillo and canela, stir until the piloncillo is dissolved, then let steep overnight at room temperature.
Step 2Place the rice and almonds in a medium bowl. In a medium saucepan, bring the remaining 6 cups water to a simmer, then pour in the canela-piloncillo “tea.” Pour the simmering mixture over the rice and almonds and let sit at room temperature for 2 to 3 hours.
Step 3Using an immersion or stand blender, blend the rice and water mixture, then pour it through a fine mesh strainer into a pitcher. Stir in the vanilla extract and add brown sugar to taste. Refrigerate the horchata until chilled before serving over ice.