Below is the title page of a delightful 1886 cook book which also contains much help on how to manage a household. I rescued this old book from a deserted and dilapidated house when I was a teenager, over 50 years ago.
Below is the recipe for Egg Nogg. I have been using it for over 40 years.
The Maltese cross beside the recipe title indicates that the author has tried the recipe and found it suitable. Here are a few notes that may help.
The egg whites and yolks must be carefully separated so that no yolk gets in the whites, else the whites will not beat up. Notice that you need only 3 of the egg whites. I crack the egg into a bowl and then use a large spoon to lift out the yolk, allowing the white to fall off into the bowl.
Rich milk means milk from a cow breed that gives milk with lots of butter fat. All milk today has a fixed amount of butter fat controlled by the dairy. You could try adding a little heavy cream to the milk, but I like a less rich egg nogg prepared with milk from the grocery store shelf, low fat milk is also good.
Best brandy means it is at least 100 proof. You will have to use an extra 1/4 cup of brandy if you have 80 proof. I have used apple brandy, rum; both light and dark, and whiskey. They are all good, with their own distinctive taste.
Note that the egg whites are whipped in, not folded in, so that they do not float a lot on top. I find floating egg whites to be as annoying as foam floating on beer.