In our vanilla-scented version of eggnog, two liquors are whisked into a custard base—rum and bourbon—a combination that makes this drink the perfect headliner for your next holiday party.
Put egg yolks, 3/4 cup sugar, vanilla seeds, and salt in a large heatproof bowl. Set bowl over a pan of simmering water, and whisk constantly until mixture is pale and thick, about 5 minutes. Whisk in milk, bourbon, and rum until combined; remove from heat.
Beat egg whites and remaining 1/2 cup sugar in the bowl of an electric mixer until soft peaks form; whisk into milk mixture. In a clean bowl, beat cream until soft peaks form; whisk into milk mixture. Refrigerate eggnog until ready to serve, up to 1 day; whisk before serving. Sprinkle nutmeg over each serving.
The eggs in this dish are not fully cooked, so it should not be prepared for pregnant women, babies, young children, the elderly, or anyone whose health is compromised.