Step 1Warm milk in medium nonreactive saucepan until tiny bubbles appear.
Step 2Meanwhile, whisk yolks and sugar in medium bowl until pale yellow. Add cornstarch and salt to yolks and whisk well. Pour warmed milk into yolk mixture 1/2 cup at a time while continually stirring.
Step 3Return mixture to saucepan and cook over medium heat, stirring constantly until mixture thickens. Remove from heat and scrape into bowl. Whisk in vanilla, then cover with plastic wrap laid directly on surface and chill completely, about 1 hour. Whisk pastry cream until smooth before using.
Coconut Variation: Replace 1 cup milk with 1 cup canned coconut milk and omit vanilla.