Put the cardamom, ginger, cinnamon, allspice berries, white peppercorns and orange zest in a jar and pour on the rum. Cover and leave for 24 hours.
Put all this into a large saucepan. Add the other ingredients and heat gently, stirring to help the sugar dissolve. Don’t let the mixture boil. Serve warm, being sure to add some dried fruit and almonds to each glass.