Whisk together the egg yolks and half of the sugar.
In a medium saucepan, combine the milk, cream, remaining sugar and salt.
Heat over medium heat until steaming.
Slowly whisk the hot cream mixture into the egg yolks.
Return the mixture to the saucepan.
Cook over medium-low heat, stirring constantly, until the custard reaches 170–175°F (77–79°C).
Remove from the heat and stir in the vanilla extract.
Strain through a fine-mesh sieve.
Cover and chill for at least four hours, preferably overnight.