The Rum Runner dates back to the 1950s, when it was created at a Tiki bar called Holiday Isle in Islamorada, Florida. Like many a tropical cocktail, it incorporates rum, banana liqueur and grenadine. It also uses blackberry liqueur, considerably less common, which adds depth of flavor and even a slight tannic touch. As seems to happen with so many midcentury tropical-inspired cocktails, recipes for the Rum Runner have branched off over the years. The various ones out there diverge quite a bit, and it’s unlikely you’ll come across two that are exactly the same. Fruit juices typically used include lime, orange, pineapple or any combination of the above. This recipe is a bit less saccharine and more sophisticated than many others, since it eschews the spiced and coconut-flavored rums you’ll sometimes see and opts for lime juice over orange. But really, you should feel free to tweak this drink in any way you like, including playing with ingredients and proportions. There’s no real wrong way to make a Rum Runner, as long as you come up with something you enjoy drinking.