1 tablespoon sugar
5 ounces milk
1 vanilla bean
Whisk the egg yolk and sugar together in a saucepan.
Heat the milk and vanilla bean together, in a separate saucepan, until little bubbles appear around the perimeter of the pan (almost boiling).
Remove the vanilla bean and stir the milk into the egg yolk mixture slowly. Return to the heat and cook until sauce starts to thicken.
Strain if desired and cool.