In large saucepan combine rice, 1 cup sugar and 8 cups milk. Cook, covered, until the rice is tender, stirring frequently (about 1 hour).
In a mixing bowl combine eggs, 2 cups milk, ¼ cup sugar, and vanilla. Beat well to combine.
When the rice is tender, add egg mixture; cook until mixture just starts to boil, stirring constantly. Remove from heat and stir in raisins if using; cool then chill. (It will thicken as it cools.)
Lamb’s always served it cold with a sprinkle of cinnamon on top, but I love it warm. It's great either way.