Step 1: Prepare the Vanilla Custard Base
Heat the cream and milk: In a medium saucepan, combine the heavy cream, whole milk, and half of the sugar (3/8 cup). Split the vanilla bean lengthwise, scrape out the seeds, and add both the seeds and the pod to the saucepan. Heat the mixture over medium heat until it begins to steam, but do not let it boil. If using vanilla extract, add it after the mixture is heated.
Whisk the egg yolks: In a mixing bowl, whisk together the egg yolks, remaining sugar, and salt until the mixture is pale and slightly thickened.
Temper the eggs: Gradually pour the hot cream mixture into the egg yolk mixture while constantly whisking to prevent the eggs from curdling.
