Add rice, almonds, 1 cups water and cinnamon stick in a blender and blend to make a coarse paste.
Add the remaining water and transfer the mixture in a glass jug and cover and keep on the counter top for 8-10 hours.
Strain the mixture using a fine mesh strainer.
Add condensed milk, milk, vanilla extract and sugar and mix well.
Refrigerate for a few hours.
Serve chilled with a few ice cubes.
Traditionally milk is not added to Horchata but I personally like the taste of milk and condensed milk. If you are not adding milk, replace the amount with water. You can replace almonds with any other nuts of your choice.