Vanilla Pudding

In medium saucepan, combine sugar, cornstarch and salt. Gradually stir in milk. Cook over medium heat until mixture boils and thickens, stirring constantly. Boil 1 minute. In small bowl, stir about 1/3 of hot mixture into egg yolks. Stir yolk mixture into hot mixture; blend well. Cook until mixture bubbles, stirring constantly. Remove from heat; stir in margarine and vanilla. If desired, spoon into individual dessert