Ingredients:

  Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
2         ounces        Dark Rum 
1         ounce         Campari 
1/2       ounce         Falernum

Preparation:

Shake ingredients with cracked ice. Strain into a chilled cocktail glass. Garnish with a lime twist.

Note: If you don't have Falernum, you "can" substitute Grenadine, although it isn't quite the same thing.