In a large saucepan, combine the Arborio rice and 2 cups of milk. Bring it to a gentle simmer over medium heat. Stir occasionally to prevent the rice from sticking to the bottom of the pan.
Cook the rice for 15-20 minutes, or until the rice is tender and has absorbed much of the milk, stirring occasionally. If the milk evaporates too quickly, add an extra splash of milk during cooking.
Make the Custard:
In a separate bowl, whisk the egg, sugar, and salt together until smooth. Set aside.
Add More Milk & Cream:
Once the rice is tender, add the remaining 2 cups of milk and heavy cream to the pot with the cooked rice. Stir well to combine.
Continue cooking on medium heat, stirring frequently, until the mixture thickens slightly (about 5-8 minutes).
Temper the Egg:
To prevent the egg from scrambling, you’ll need to temper it. Slowly ladle a bit of the hot rice mixture into the bowl with the whisked egg, stirring constantly to bring the temperature of the egg up without cooking it.
Gradually add this tempered egg mixture back into the pot with the rice, stirring constantly. Continue to cook and stir the pudding for another 5-7 minutes, or until it thickens to a creamy custard consistency.
Finish the Pudding:
Once the rice pudding has thickened, remove the pot from the heat. Stir in the vanilla extract and butter (if using) for extra creaminess and flavor.
Let the pudding cool slightly. It will continue to thicken as it cools. You can serve it warm or refrigerate it for a few hours to enjoy chilled.
Serve:
Spoon the rice pudding into individual bowls and sprinkle with a little cinnamon if desired. You can also add a touch of extra vanilla or a few raisins if you like!
