From its origins in Jamaica, the allspice berry has been prized for its exceptional tastes of clove, cinnamon, and nutmeg and a pepper note that dazzles the palate. Also known as "Pimento Dram."
I have used this in the past. Its great!
You will need only a tiny 1/8 tsp of this allspice dram, equal parts of a good light rum, Demerara Rum, Myers’s Dark Rum, lime juice to taste, a sprig of mint, and a little white grapefruit juice or grapefruit bitters. Lots of crushed ice and ideally a rock candy on a stick. Mmmmm.