Add all of the ingredients to a medium sized pot and whisk well until thoroughly combined.
Set on the stove top over medium heat and allow to heat for 5-8 minutes on a low simmer, stirring often to allow the flavors to combine.
Allow to cool slightly before pouring the eggnog into a metal bowl nested inside a larger bowl filled with ice to form an ice bath. Allow to sit for 20-30 minutes to chill.
Serve fresh topped with additional cinnamon if desired.
Notes
All nutritional information are estimations and will vary. Estimations do not include optional ingredients.