Blend the sugar, cornstarch and salt in a pan ( about 2 qt. size).Combine the milk and egg yolks and then slowly stir them into the sugar mixture. Over medium heat, stir mixture continuously until mixture thickens and reaches a boil. Allow to boil for about 1 minute, stirring constantly. Remove from heat and add the butter and the vanilla. Stir well and then pour into desert dishes. Allow to cool a bit first, then refrigerate.
