Separate the eggs and place the yolks in a bowl. The whites can be placed in another bowl, covered, and refrigerated for use later in another recipe.
Combine the sugar and yolks in a mixing bowl. Whisk them together with a blender or whisk until pale and creamy.
Add the milk and cream to a saucepan. Heat over medium heat and bring it to a gentle simmer.
Slowly whisk the milk mixture into the egg mixture in a thin, steady stream to avoid scrambling the eggs.
Transfer the mixture to the saucepan and cook on medium heat until the eggnog thickens to your desired consistency.
Whisk in the vanilla and nutmeg.
Serve immediately or refrigerate for up to three days. Garnish with extra nutmeg if desired.
