Americans love the boozy holiday beverage. So let's take a look back at its history, and see what makes it so special.
According to PBS, most historians say that eggnog started in medieval times as posset, which is a drink made with hot milk and curdled with booze like ale or sherry. It was usually sweetened and spiced. Monks at the time would add whipped eggs and figs to the mix.
Back in those days, milk, eggs, and sherry were really expensive. So posset was often used in toasts to prosperity and good health. USA Today says it was commonly consumed by the British aristocracy in the winter.
Eventually, the drink made its way over to the American colonies in the 1700s, where it evolved into the eggnog we know today. Most families lived on farms, so it was much easier to get the milk and eggs needed for the drink. Sherry was still expensive though, so many Americans used whiskey or rum instead.
George Washington even had his version of the drink that he'd serve to visitors at Mount Vernon. According to TIME, the drink included cream, milk, sugar, brandy, rye whiskey, Jamaica rum, and sherry. Unfortunately, he forgot to write down how many eggs he used in the recipe, though food experts say that about a dozen would work.
Many families in the U.S. have passed down eggnog recipes for several generations. That includes Christina Ellis, who is part of the family that runs Ellis Island hotel-casino in Las Vegas.
Ellis Island sells their Holiday Nog in limited quantities every year around Christmastime. According to Christina, the drink came from her great-grandfather, Frank Ellis Sr., who got the recipe from a fellow passenger on a ship taking him from Italy to the United States in 1953.
The recipe was kept within the family up until 2002 when the brewmaster at Ellis Island insisted that the family should sell it to the public. 15 years later, the hotel-casino still shares their Holiday Nog with those lucky enough to get a bottle.
This year Ellis Island has 2,800 bottles of eggnog available for around $30 per bottle and $6 for a glass. You can get it at the casino itself, or at all 11 Village Pub locations in Southern Nevada.