1. Dissolve sugar in water in a large frying pan (skillet) over gentle heat, stirring often with a metal spoon. Add kaffir lime leaves, cinnamon bark, cardamom and mace, if using. Bring to a gentle boil, then simmer for 5 minutes.
2. Halve plums and remove stones if possible. Add to pan cut side up. Spoon over syrup. Poach for 7-10 minutes until tender, spooning syrup over once or twice. Cool plums in syrup, spooning over syrup 2-3 times.
3. Serve with Greek yoghurt, or vanilla ice cream (or hokey pokey ice cream!). If liked, crumble over ladyfinger biscuits before serving.