Whisk the egg yolks and sugar together in a large bowl until creamy. Set aside for later.
Add the milk and heavy cream to a large saucepan with the cinnamon, nutmeg, cloves, anise, and salt.
Stir often as you bring this mixture to a very gentle simmer over medium-low heat.
Turn heat down to low while tempering your egg and sugar mixture.
To temper your eggs, add two large spoonfuls of the milk and cream mixture to the egg mixture. Stir until completely combined. Repeat one to two more times.
Pour the tempered egg mixture back into the saucepan with the remaining hot milk mixture.
Continuously whisk over medium heat until the eggnog thickens slightly (about 3-5 minutes).
Pour the eggnog through a strainer and into a pitcher or other large container of choice. At this point, you can add liquor if you wish.
Cover with plastic and refrigerate for 2-4 hours or overnight for the best result.
Pour into glasses, top with whipped cream, and lightly sprinkle each serving with cinnamon and whipped cream. Serve.