In a heavy saucepan, add your scraped vanilla bean and milk together and bring to a simmer.
4 cups Whole milk, 1 Vanilla Bean
Whisk the egg yolks, sugar, cornstarch and pinch of salt together in a bowl. Whisk until the mixture lightens in color and becomes a pale yellow.
5 Egg Yolks, ⅔ cup Granulated Sugar, ½ cup Cornstarch, Pinch Kosher Salt
Temper the egg mixture by slowly whisking in the hot milk to the egg mixture together until homogenous.
Return the mixture to the saucepan and bring to a boil, stirring constantly over medium heat.
When the pastry cream comes to a boil, continue to whisk constantly and boil for up to 2 minutes. The pastry cream should reach 200F.
Remove from the heat and strain into a clean bowl. Stir in the butter and mix until the butter is melted and mixed into the cream.
3 tablespoons Unsalted Butter
Cover with plastic film placed directly in contact with the surface of the cream to prevent a skin from forming and place in the fridge to cool.
Before using, whip the chilled pastry cream until smooth before using!