In a medium bowl, whisk the egg yolks and sugar together until light and creamy. Set aside.
In a saucepan over medium-high heat, combine the milk, cream, nutmeg, cloves and salt. Stirring frequently until it comes up to a low simmer. Temper the egg mixture by ladling a small amount of the hot milk mixture to the egg yolks and whisking quickly to incorporate well.
Repeat a couple times more until the egg mixture is hot. Gradually whisk the egg mixture completely back into the hot milk in the pot and place back on the stovetop. Whisk constantly for about 5 minutes, until the mixture is just slightly thickened. Remove from heat and stir in vanilla.
Pour the eggnog into a serving pitcher and cover with plastic wrap. Chill until ready to serve.
Garnish with whipped cream and cinnamon, if desired. Store in the fridge for up to one week.