In medium size pot, add sugar, cornstarch and salt. Mix.
Slowly whisk in milk and whisk often over medium heat until thickened and bubbly.
In small bowl, lightly whisk egg yolks
Drizzle a small amount of hot mixture into egg yolks, whisking quickly to temper the eggs
Return pot to heat and slowly, pour egg mixture into pot, whisking rapidly
Cook for 2 minutes more or until thickened
Pour into bowl and cover with plastic wrap, allowing the plastic to touch the surface of the custard. Chill completely.