It’s not often one needs to make a batter for a cocktail, but so it is with the Tom and Jerry, a Christmas party staple in the American Midwest. The drink begins with a frothy batter of separately beaten egg whites and yolks folded together and mixed with sugar, vanilla, and warm spices such as cinnamon, nutmeg, and allspice. Cream of tartar is occasionally added to ensure the beaten egg whites maintain their stiff peaks. When served as a party punch, this sweet, eggy batter is often ladled out of special Tom and Jerry punch bowls. Drinkers add hot milk (or water) and rum or brandy (adding both is also popular) into matching Tom and Jerry cocktail mugs and drop the creamy batter on top. After stirring, they’ll garnish the cloud of foam on the brim with an additional sprinkle of nutmeg for a delicious, warm revamp of the classic eggnog.

The Tom and Jerry’s origins are frequently traced back to a clever publicity stunt orchestrated by the British journalist Pierce Egan. The story goes that Egan added brandy to eggnog to create a signature cocktail to promote his 1821 book, Life in London, or The Day and Night Scenes of Jerry Hawthorn Esq. and His Elegant Friend Corinthian Tom. A subsequent play based on the book, Tom and Jerry, or Life in London, also produced in 1821, has additionally been associated with the beverage. While this origin story remains unverified, Egan’s work did make a meaningful contribution to the drinking world: the phrase “Tom and Jerrying,” which means indulging in loud, drunken behavior.

No definitive records exist about the drink’s first appearance stateside, but in 1862, the famed New York bartender Jerry Thomas published a recipe for a Tom and Jerry in his book, How to Mix Drinks, Or, The Bon-vivant’s Companion. That recipe calls for an astounding 5 pounds of sugar and 12 eggs with half a glass of Jamaican rum and spices. (Modern variations of the punch exercise more caloric modesty.)

Historians are unclear as to why the Tom and Jerry has become such a Christmas staple in the Midwestern United States, but it was popular enough to merit a cottage industry of Tom and Jerry drink sets, consisting of punch bowls and mugs inscribed with the drink’s name in Old English font. Milk glass Tom and Jerry sets produced by the Hazel-Atlas and Mckee Glass companies were fairly common in the 1940s through 1960s. A New York Times article about the cocktail quotes author Jim Draeger, who wrote a book on Wisconsin’s historical taverns, as surmising that the Tom and Jerry became a Wisconsin staple because the state has an affinity for brandy drinks, and is well-known as a dairy state. The intense cold of the American Midwest has arguably solidified this warming drink’s staying power in the winter drinking traditions of the region.