In a large saucepan, combine the rice and 4 cups of whole milk. Bring the mixture to a boil over medium heat, stirring frequently to prevent the rice from sticking to the bottom of the pan. Do not leave unattended at this step.
Once the mixture reaches a boil, reduce the heat to low. Let the rice simmer, uncovered, for about 20-25 minutes, stirring occasionally, until the rice is tender and the mixture starts to thicken.
Stir in the sweetened condensed milk, granulated sugar, salt, vanilla extract and ground cinnamon. Continue to cook for an additional 10-15 minutes, stirring frequently, until the pudding is thick and creamy.
Taste and adjust the sweetness to your liking. If the pudding is too thick, you can add a little more milk to reach your desired consistency.
Spoon the rice pudding into serving bowls. If desired, sprinkle with ground cinnamon and nutmeg for garnish. You can also top with fresh fruit or a dollop of whipped cream for an extra indulgent treat.