In a saucepan, heat cream, milk, salt + scraped vanilla bean over medium until steaming (not boiling).
In a bowl, whisk yolks + sugar until pale.
Temper: slowly whisk warm milk into yolks.
Return to saucepan, cook on low stirring constantly until thick enough to coat the spoon (170–175°F).
Strain into a bowl to ensure silkiness.
Chill completely (4 hrs or overnight is best).