This is a Papa Doble, a Daiquirí that Hemingway was fond of drinking at the Floridita Bar in Havana. I made it from a recipe that A. E. Hotchner wrote down one day while hanging with Papa at the fabled watering hole.
That’s Hemingway below, of course, sitting at his favorite spot at the bar, between Spencer Tracy and his wife Mary.
Hotchner’s recipe calls for the juice of two limes, the juice of one half grapefruit, six drops of cherry brandy and three ounces of Bacardi rum (or Havana Club rum if you can find it.) You put this in a blender 1/3 filled with ice and blend at high speed until the mixture turns the color of “the sea where the wave falls away from the bow of a ship when she is doing thirty knots”, as Hemingway helpfully explains.
It’s a wonderfully refreshing drink, slightly tart but still festive. Don’t try to drink as many of them as Hemingway could at one sitting, sixteen by some reports — you’ll live longer.
Update — this recipe produces a drink that’s too strong, not for Papa, maybe, but too strong for me. I recommend adding twice as much grapefruit juice, which will produce enough for three medium-sized Daiquirís. If you want it to taste more like a traditional Daiquirí, add more cherry brandy or a bit of cane syrup to sweeten it. I myself find the unsweetened drink more satisfying — more bracing, like a breeze coming in off the ocean.