Bring to a boil then reduce to a simmer. Cook until the rice has absorbed nearly all of the water.
Add the milk in three equal parts, bringing the liquid back to a simmer and cooking until nearly all of the milk has been absorbed before adding more milk. Stir frequently.
Add the vanilla extract with the last addition of milk. Cook until all of the liquid has been absorbed.
Remove the porridge from the heat and allow to cool for 5-10 minutes before serving.
Notes
Adding the liquids gradually: While you can add the liquid all at once, adding it in batches makes it easier to bring to a simmer and stay hot. This helps it cook faster and reduces your chances of scalding the milk.
Sugar: It's not a typo - This recipe doesn't call for sugar because it's traditionally served with cinnamon and sugar sprinkled on top. Whether you're serving it that way or with fresh or dried fruit, I promise you don't need to add it during the cooking process.
Storage: Leftovers can be stored in an airtight container in the fridge for up to 5 days. Milk can be added during the reheating process if the porridge has become too thick.