In a small-sized saucepan add 1/2 cup uncooked Kokuho Rose rice and 1 cup of water.
Cover the rice with a lid and bring increase the heat to a small boil. Then, stir the rice, and reduce the heat to low. Keep the saucepan covered and stir occasionally (if the heat is too high then the rice will stick to the bottom and burn).
In a separate medium-sized pot heat up 6 cups of oat milk until the milk is warm.
After about 10-12 minutes the rice will absorb the water. Keep the heat on low and the saucepan covered. Stir occasionally.
Once the rice has absorbed the water, add the rice to the pot with the warmed oat milk. Add in the lemon rind and orange rind to the warmed oat milk.
Increase the heat slightly and stir the rice in with the oat milk. Keep the pot uncovered and the milk on a simmer for about 15 minutes. Continue to stir every few minutes.
After 15 minutes, add in 3/4 cup of sugar and continue to stir. The sugar will slowly help to thicken the rice pudding.
Add in one tablespoon pure vanilla extract.
Add in one tablespoon of Cointreau (optional).
Let the rice pudding cook on a low simmer uncovered for about 20 minutes or until the rice is cooked. Stir often so that the rice doesn't stick to the bottom of the pot. You will slowly feel the rice pudding start to thicken.
In a small cup mix 1/2 tablespoon of cornstarch with 1 tablespoon oat milk. Mix well together and set aside.
After the rice pudding has been cooked with the sugar for 20 minutes, increase the heat slightly and add the diluted cornstarch to the rice pudding. Stir consistently.
The sugar and corn starch will thicken the rice pudding. Stir occasionally for another 5-10 minutes.
After the rice pudding has been cooked for 5-10 minutes with the cornstarch, remove the rice pudding from the heat. You will see the rice pudding start to thicken but for this recipe, the rice pudding won't be super thick when it's still warm in the pot.
Using a ladle or large spoon, scoop the rice pudding into individual bowls and top with sprinkled cinnamon.
Rice pudding tastes delicious warm or cold! Keep in mind that the rice pudding will thicken more once it cools.