2/3 c. sugar
3 tbsp. cornstarch
1/2 tsp. salt
3 c. milk

Mix sugar, cornstarch, and salt in a saucepan. Stir in milk gradually. Cook over medium heat, stirring constantly, until mixture thickens and boils 1 minute. Add to mixture:

3 egg yolks, slightly beaten
1 tbsp. butter
1 1/2 tsp. vanilla

Boil 1 minute. Cool and put in cooked pie shell. Top with Cool Whip or a meringue.