Simmer the rice:
In a large, heavy-bottomed saucepan, combine the rice, 3 cups of milk, sugar, salt, cinnamon, and nutmeg. Stir to blend. Bring the mixture to a gentle simmer over medium heat, stirring occasionally to prevent the rice from sticking to the bottom of the pan.
Cook until thickened:
Reduce the heat to low and cook uncovered for 25ā30 minutes, stirring frequently. The rice should be tender and the mixture thick and creamy, with the grains suspended in the milk mixture.
Add eggs:
In a small bowl, whisk together the remaining 1 cup of milk and the eggs until fully blended. Slowly pour this into the hot rice mixture, stirring constantly to avoid scrambling the eggs.
Final cook:
Continue to cook the pudding for 5ā7 minutes over low heat, stirring constantly, until it thickens further and has a custard-like consistency.
Finish the pudding:
Remove the saucepan from the heat. Stir in the butter, vanilla extract, and raisins if using. Mix well until the butter is melted and everything is evenly distributed.
Cool and serve:
Let the pudding cool slightly before serving. Serve warm or chilled, depending on preference. Sprinkle the top with additional ground cinnamon just before serving for a warm, aromatic finish.
