While the origin stories of many cocktails are murky, the Rosita in particular appears to suffer from a soap opera–style amnesia: forgotten, found, lost, and found again. A riff on the Negroni, the Rosita cocktail seems to have made its first appearance in print in the 1974 edition of Mr. Boston’s Official Bartender’s Guide, creator unknown. But it was the late Gary “Gaz” Regan who popularized it, if indirectly. In the early aughts, the drink came to Regan’s attention by way of fellow drinks writer Terry Sullivan, who featured the recipe in an article. When queried as to where he found it, Sullivan could not recall, and the topic was forgotten. A few years later, as Regan prepared the drink for some friends, he was asked about its origins. He reached out to Sullivan again, and this time Sullivan remembered: He found the recipe in the 1991 book The Bartender’s Bible. The author? Gary Regan. “I didn’t remember putting Rosita in The Bartender’s Bible, but it’s there all right,” wrote Regan in his column for the San Francisco Chronicle in 2007. “Where did I steal that one from, I wondered.” Further digging revealed that he had come across the recipe in the 1988 edition of Mr. Boston and made a few of his own tweaks, including dialing up the tequila and adding a dash of bitters, creating the recipe that is more or less still used today. “I must have actually tested the recipe for Rosita,” Regan wrote. “Wonders never cease.”