Measure out 1 cup of rice (I used basmati rice). Wash the rice 2-3 times, until the water runs clear.
Rise out the water and add the rice to a blender, along with 3.5 cups of water and 1 cinnamon stick.
Pulse a few times, until the rice is coarsely ground and the cinnamon stick is broken up. You don’t want the rice to be finely ground, else it will overcook in the Instant Pot and can trigger a Burn notice.
Add the contents of the blender to the Instant Pot, and cook it at ‘Manual’ for 1 minute.
After 1 minute, hit ‘Cancel’ and perform a quick release of pressure.
Immediately, add 3.5 cups of water, followed by 1 cup of milk to the contents of the IP.
Stir well, and add 1 teaspoon vanilla extract and stir again.
Strain the contents of the IP through a sieve (preferably, use a fine mesh sieve), into a large bowl.
Add 4-5 tablespoons of sugar (you can add less or more as per your sweet preference). Stir to dissolve.
Add ice and keep the bowl in the fridge to chill.
Serve in glasses topped with more ice, and a sprinkle of cinnamon.