In a medium bowl, whisk together the heavy cream, milk, eggs, sugar, nutmeg, and cinnamon until blended.
Transfer the mixture to a medium saucepan and heat over medium-low heat, stirring constantly, for about 8 minutes, or until the mixture is thickened and coats the back of a spoon.
Remove from heat and stir in the vanilla extract and brandy or rum, if using.
Pour the eggnog into mugs or glasses and serve warm or chilled.
Interesting Facts
Eggnog is believed to have originated in England in the 1700s.
It was first brought to America by early settlers and has since become a traditional holiday beverage.
Eggnog can be served with a variety of mix-ins such as nutmeg, cinnamon, brandy, and rum.
The traditional recipe for eggnog calls for raw eggs, but you can opt for pasteurized eggs for a safer version.