Whisk the egg yolks in a bowl with 100g of the sugar until the mixture is pale yellow and thick
Stir in the milk, double cream, and the alcohol. You can add a little grated nutmeg or cinnamon if you like
Using a handheld electric mixer, whisk the egg whites until foamy and opaque. Add the remaining 50g of sugar and whisk the egg whites until soft peaks form when the whisk is removed
Fold in the egg whites to the mixture until well combined. Ladle the egg nog into glass tumblers and serve with a little freshly grated nutmeg over the top of each glass