In a bowl, beat the eggs and sugar until creamy. In a saucepan over low heat, heat two cups of the milk until hot. Slowly add to the egg mixture, stirring continuously. Cook over low heat, stirring, for fifteen to twenty minutes or until the mixture is thickened. Stir in the remaining milk, vanilla essence, whisky, and half the nutmeg.
Chill for three hours. In a medium bowl, beat the cream until soft peaks form. Fold into the milk mixture. Ladle the eggnog into a punch bowl and sprinkle with the remaining grated nutmeg.