01 -
In a medium bowl, whisk the egg yolks and granulated sugar together until the mixture becomes pale and creamy.
02 -
Combine whole milk, heavy cream, ground nutmeg, ground cinnamon, and the cinnamon stick in a medium saucepan. Warm over medium-high heat until the mixture reaches a gentle simmer.
03 -
Slowly pour about 60 ml of the hot milk mixture into the egg yolk mixture, whisking constantly to prevent curdling. Gradually add more of the hot liquid, a little at a time, whisking continuously until half of the dairy has been incorporated.
04 -
Pour the egg-dairy mixture back into the saucepan with the remaining milk mixture. Cook over medium heat, stirring constantly with a wooden spoon or silicone spatula, until the liquid reaches 71°C (160°F) and thickens slightly.
05 -
Remove the saucepan from the heat. Stir in the vanilla extract and discard the cinnamon stick. Allow the eggnog to cool for 1 hour at room temperature, then transfer to a pitcher or airtight container and refrigerate for at least 1 more hour, or until well chilled.
06 -
Pour the chilled eggnog into glasses or mugs. Garnish with a sprinkle of ground cinnamon and/or nutmeg if desired. Serve immediately.