Hemingway had a boozy heart and a sour tongue. His original “Papa Doble” was just a lot of rum with a splash of lime juice; this is still made for drinkers with a sour tongue but is way more palatable.
3 oz. White Rum
3/4 oz. Fresh Grapefruit Juice
1/2 oz. Fresh Lime Juice
1/4 oz. Maraschino Liqueur
Shake all ingredients with ice and strain into cocktail glass or on the rocks. Grapefruit or lime peel garnish.