Prepare the spice blend first. If you are using pre-ground spices, mix them together in a small bowl. If you are using whole spices, remove the seeds from the cardamom pod and place the seeds in a mortar with pestle with the whole black pepper. Grate in ½ teaspoon of cinnamon (I use a Microplane grater) and ½ teaspoon of nutmeg. Pulverize the spices with the pestle until finely ground.
Place the egg yolks, spices and sugar in a large bowl. Using a hand mixer on the low setting, beat until smooth and creamy. Slowly add the milk and cream and blend on low until smooth and silky, about 2 minutes. Add in the booze and stir.
Place the eggnog in a gallon Mason jar with lid, or a pitcher and cover with plastic wrap. Whatever container you use should have ample room to fold in the egg whites.
Beat the egg whites in a large bowl until semi-stiff peaks form, about 5–6 minutes. Gently fold the beaten egg whites into the base. Chill, covered, for 36 to 48 hours before digging in.
Eggnog will keep for at least 2 weeks in the refrigerator, and it does get better with age.