6 large egg yolks
1/2 cup granulated sugar
1 cup heavy cream
2 cups milk
1 1/2 teaspoons freshly grated nutmeg
Pinch of salt
1/4 teaspoon vanilla extract
1. In a medium bowl, whisk together the egg yolks and sugar until light and creamy.
2. In a saucepan, bring the cream, milk, nutmeg and salt to a bare simmer, stirring often. Slowly ladle in 1/2 cup or so of the hot milk to the egg mixture, whisking vigorously. Ladle in another 1/2 cup, continuing to whisk vigorously the entire time. Do this until all the hot milk has been added to the eggs and the mixture is well combined.
3. Pour the tempered egg mixture back into the saucepan of milk on the stove, whisking quickly, and cook the mixture, stirring constantly, until it reaches 160 degrees F on a thermometer.
4. Remove from the heat and stir in the vanilla and rum (if using).
5. Pour the eggnog into a bowl and cover with plastic wrap. Refrigerate until thoroughly chilled.