Start by separating the egg yolks from the whites. In a large bowl, whisk together the yolks and sugar. Blend until you achieve a pale and creamy texture. This reaction incorporates air and creates a lovely base for your eggnog.

In a saucepan over medium heat, combine the milk and cream. Stir gently until heated but not boiling. Remove it from the heat when steam rises. Add in the vanilla, almond extract, and grated nutmeg. Stir to combine.

Now comes the technical part. Gradually add the warm milk mixture into the yolk mixture, whisking constantly. This process—known as tempering—prevents the eggs from scrambling. Keep pouring slowly until fully mixed.

Pour the combined ingredients back into the saucepan. Cook over low heat, stirring constantly until the mixture thickens slightly. It should coat the back of a spoon. Avoid boiling. Once thickened, take it off the heat.

Let the mixture cool at room temperature, then refrigerate for at least 2 hours or overnight. As it chills, the flavors meld and deepen, making it even more delicious.

Before serving, whisk the eggnog again to incorporate air. You can also stir in your choice of alcohol, if using. For those who enjoy a festive flair, sprinkle freshly grated nutmeg or ground cinnamon on top.