1 oz of white rum (or Light Rum)
1 oz of dry vermouth
1 oz of white creme de cacao (or chocolate liqueur)
1 oz of Mandarin Juice
1/2 oz of Lime Juice
2 oz of grapefruit juice
1 tsp of caster sugar (or sugar)
Shake with a glassful of broken ice and pour unstrained into a collins glass.