Charles H. Baker, author of The Gentleman’s Companion, discovered this wonderful drink in 1937 at La Cucaracha Bar in Mexico City.
Back in those days, grenadine was still made from pomegranates, instead of the red corn syrup you’re more likely to find today. Since it makes up such a large proportion of the drink, you’d do well to hold out for the good stuff (or substitute crème de cassis, one of our favorite sweeteners to pair with tequila).