Mix the cooked rice, 1 1/2 cups milk, sugar and salt. Cook uncovered over medium heat for about 15-20 minutes.
Whisk egg and remaining milk in a bowl. Add about 1 cup of the hot rice mixture to the egg while stirring.
Stir the egg mixture and raisins into the rice. Cook 2 minutes more.
Remove from heat and stir in butter and vanilla.
Serve warm and garnish with whipped cream and a sprinkle of nutmeg and cinnamon.
(Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.)