Bring 1½ cups water to a boil in a saucepan; stir rice into boiling water. Reduce heat to low, cover, and simmer for 20 minutes.
In a clean saucepan, combine 1½ cups cooked rice, 1½ cups milk, sugar, salt, and raisins. Cook over medium heat until thick and creamy, 15 to 20 minutes. Stir in remaining ½ cup milk, beaten egg, cook 2 minutes more, stirring constantly. Remove from heat and stir in butter and vanilla.
Recipe by Family & Friends Recipes at https://recipes.van-ginneken.com/desserts/606-2/