Bring the cream and butter just to a simmer in a saucepan over moderate heat. Remove from heat, then add chocolate and then the rum, stir gently with a heatproof rubber spatula until ganache is smooth.

Pour into a bowl, cover and chill the ganache mixture for 2-3 hours or until firm.

Remove the ganache from the fridge and roll into 25 balls. When you’re ready to coat them simply pour the desiccated coconut into a shallow bowl or dish. Drop two or three truffles onto the coconut and shake the dish to and fro, proceed with the remainder. Chill on a tray until needed.