Place the rice in a strainer or colander and rinse it under running water for a couple of minutes.
Then, pour the rice into a large pot with six cups of water and the cinnamon stick. Place the pot on the stove and simmer, half-covered, for approximately one hour.
When most of the water has evaporated, the rice will have a thick paste like consistency. Turn off the stove and let it sit for fifteen minutes before blending.
Remove the cinnamon stick. Place the rice, preferably in two batches, into the blender and blend for a few minutes until you have a completely smooth, even paste. There should be no lumps.
Then add the milk, condensed milk, and vanilla extract. Taste; and if necessary, add additional sugar. Blend for a couple more minutes, and it's ready.
To serve, fill the glasses halfway with crushed ice and fill the rest of the glass with chicha. Decorate with extra condensed milk and cinnamon powder.