1Combine milk, cloves, cinnamon and the first portion of vanilla in a large saucepan. Heat on low for five minutes. Slowly bring to a boil.
2In a large bowl, combine egg yolks and sugar. Whisk together until fluffy.
3Slow whisk the hot milk mixture into the egg yolks, a little at a time.
4Pour back into the saucepan and cook over medium heat, stirring constantly, for about 3 minutes, or until thick. Be careful not to let it boil.
5Strain into a large pitcher, cover and let cool for about an hour.
6Stir in the cream, nutmeg, and second portion of vanilla. Stir in rum, if desired.
7If you would like to include the egg whites, beat them until stiff and slowly add 1/4 c sugar. Gently fold into the egg nog.
8Refrigerate overnight before serving.