Beat egg yolks in a large mixing bowl until thick and lemon colored. Gradually add 1/2 cup sugar, beating constantly. Stir in milk, bourbon, and rum, blending well.
Beat egg whites (at room temperature) in a large mixing bowl until foamy. Gradually add 1/2 cup sugar, 1 tablespoon at a time, beating until stiff peaks form. Gently fold egg whites into milk mixture, blending well.
Beat whipping cream until foamy; gradually add remaining sugar, 2 tablespoons at a time, beating until soft peaks form. Fold whipped cream into milk mixture. Ladle into serving cups, and sprinkle each serving with nutmeg.