Combine sugar, cornstarch and salt in saucepan. Gradually add milk, stirring until mixture is smooth. Bring to a boil over medium heat, stirring constantly. Boil, stirring, 2 minutes. Remove from heat.
Stir half of hot mixture into egg yolks; combine with rest of hot milk mixture in saucepan. Cook, stirring, over low heat until mixture boils and is thick enough t