In saucepan, blend sugar, cornstarch, and salt; add milk. Cook and stir over medium heat until thickened and bubbly. Cook and stir 2 minutes more. Remove from heat.
Stir small amount of hot mixture into egg; return to hot mixture; cook and stir 2 minutes more. Remove from heat; blend in butter and vanilla.
Pour inter sherbet dishes; chill. Make 4 or 5 servings.
Variations:
Chocolate Pudding: Follow directions for Vanilla Pudding, increasing sugar to 1 Cup. Add 2 ounces chopped unsweetened chocolate along with the milk.
Butterscotch Pudding: Follow directions for Vanilla Pudding, substituting brown sugar for the granulated sugar. Increase the amount of butter or margarine to 3 Tablespoons.
Banana Pudding: Reduce vanilla to 1/2 Teaspoon and add 1 Teaspoon Banana Extract.