Light rum, Maraschino Liqueur, Lime juice, Grapefruit juice, Lime
Shake, strain, straight up, coupe, garnish.
Some may need some simple. PDT recommends Banks 5 Island rum.
Originally posted as 2oz rum, 1/2oz Maraschino and Lime, 1 oz Grapefruit, 1/2oz simple. According to the PDT this version did not have additional sugar because Hemingway was a diabetic.