Add egg yolks and Swerve to a large bowl, and using a whisk or an electric mixer (easier), beat them until light, fluffy, and all the sweetener is completely dissolved.
Set aside.
Add almond milk, heavy cream, cinnamon and nutmeg to a medium saucepan and bring just to a boil, stirring every so often.
Remove from heat and gradually temper the hot mixture into the egg and sugar mixture.
Tempering means adding the hot milks little by little to your egg mixture while whisking constantly, so your eggs don't curdle.
Return everything to the saucepan, and cook over medium/low heat for roughly 8-10 minutes, or until your mixture reaches 160°F/70°C.
Remove from the heat and sieve onto a medium mixing bowl.
Stir in vanilla and liquor of choice, to taste.
Cover and transfer to the refrigerator to chill.Your eggnog will continue to thicken while chilling.