Cook rice according to package directions until tender. Combine sugar, cornstarch and salt. Add milk and sugar mixture to rice.
Heat to boiling; boil 1 minute, stirring constantly. Remove from heat. Stir in butter and vanilla. Separate eggs (whites will not be used) and beat yolks. Slowly stir about 1 cup of the hot rice mixture into the beaten egg yolks in a bowl. Blend with the remaining mixture in saucepan. Cook over medium heat, stirring frequently, just until mixture starts to bubble. Serve warm or cold, plain or with favorite topping.
Optional: One or more of the following ingredients can be added after the egg yolks and before final cooking. 1/2 c Raisins 1/2 c Chopped Nuts 1/2 c Chopped Apples 1 t Cinnamon