In a medium bowl whisk together the egg yolks and sugar. Set aside while you prepare the milk mixture.
In a medium saucepan over medium heat, warm the milk, cream, and nutmeg until it reaches a simmer.
Ladle a big spoonful of the hot milk mixture to the eggs, whisking vigorously. Repeat, adding a big spoonful at a time, to temper the eggs.
Once the hot milk has been added to the eggs, pour the mixture back into the saucepan on the stove.
While whisking, cook over medium-low heat until the mixture thickens, about 4 minutes. Note that It will thicken even more as it cools down.
Remove from heat and stir in the vanilla and salt.
Pour the eggnog through a sieve into a jug and allow it to cool down completely before covering and chilling for a minimum of 3 hours but up to 3 days.
Serve with a sprinkle of nutmeg, and freshly whipped cream. Add a splash of bourbon for when the kids go to bed!