eat the milk without scalding. Whisk the sugar and egg yolks in a bowl until well blended. Slowly add the hot milk, whisking constantly. Return the mixture to the pot used to heat the milk. Remove about 1/3 cup of the mixture from the pot. Whisk in the teaspoon of corn starch and return the corn starch/milk mixture to the pot and whisk to blend. Add the teaspoon of vanilla and whisk to blend. Stir constantly over medium heat until the mixture thickens and coats a spoon. Chill to thicken further.