How to Make It
Put the egg yolks in a medium bowl and set the bowl over a saucepan of simmering water. Add 1/4 cup plus 2 tablespoons of the sugar and whisk over low heat until pale yellow and thick, about 5 minutes. Whisk in the milk, bourbon, rum and brandy and transfer to a large bowl.
In another large bowl, whisk the egg whites with the remaining 1/4 cup plus 2 tablespoons of sugar until very soft peaks form. Stir the whites into the yolk mixture. In a medium bowl, beat the heavy cream until lightly thickened. Fold the whipped cream and nutmeg into the eggnog and chill thoroughly. Whisk to reblend before serving.