1Separate six egg yolks from their whites and put the yolks in a bowl. Reserve the egg whites for another use.
2Add three quarters of a cup of granulated sugar to the egg yolks.
3Whisk the egg yolks and sugar until pale.
4In a saucepan, combine two cups of whole milk, one cup of heavy cream, one teaspoon of vanilla, half a teaspoon of nutmeg and a pinch of cinnamon.
5Bring the milk mixture to a boil, then turn off the heat.
6Temper the eggs by slowly adding a portion of the hot liquid to the egg mixture while whisking constantly to prevent curdling.
7Add the tempered egg mixture to the saucepan with the remaining hot milk mixture and stir to combine. If there are curdles, pass the mixture through a strainer.
8Add alcohol at this point, if desired.
9Pour the eggnog into a pitcher and let it cool before serving.