1. Off heat, whisk eggs, yolks, sugar, and salt in heavy 3- or 4-quart saucepan. Stir in milk, one-half cup at a time, blending well after each addition. Heat slowly over lowest possible flame, stirring constantly, until custard registers 160 degrees on instant read thermometer, thickens, and coats the back of a spoon, 25 to 30 minutes. Pour custard through sieve into large bowl; stir in liquor, vanilla and grated nutmeg. Cover with plastic wrap and refrigerate until well chilled, at least three hours and up to three days. 2. Just before serving, whip cream in medium bowl to very soft peaks and gently fold into custard mixture until incorporated. Serve in chilled punch bowl or cups, garnishing with optional grated nutmeg. Adding the milk to the eggs in small increments and blending thoroughly after each one helps ensure a smooth custard. To prevent curdling, do not heat custard beyond 160 degrees. If it does begin to curdle, remove from heat immediately and pour into a bowl set over a larger bowl of ice water to stop the cooking, and proceed with recipe. You can omit the brandy to make a non-alcoholic eggnog, but you should also decrease the cream to 1/4 cup in order to keep the right consistency. For the same reason, increase the cream to 3/4 cup if you choose to add another 1/2-cup alcohol for a high-test nog. serves 12-16