Crème Pâtissière

In a medium pot, scald milk. (If using vanilla bean, scrape seeds into milk before scalding. Remove from heat and let steep 20 minutes. Remove the bean pod.) Whisk together sugar, salt, egg yolks and cornstarch until smooth and lightened. Temper the eggs by streaming in a ½ cup of milk while whisking, then whisk eggs back into the milk in the pot.

Whisk continuously over medium heat. Pause occasionally as mixture thickens to check for bubbles. Cook at least one full minute after reaching boiling to disable the yolks’ α-amylase, which weakens the starch. Remove from heat and stir in butter (and vanilla if not using a bean).

If necessary, strain through a fine-mesh sieve to remove lumps. Cover with plastic wrap to prevent a skin from forming. Let cool, then refrigerate.