Combine macadamia nuts and icing sugar, spread on a baking tray and bake at 160°C for 10 minutes. Stand to cool, then chop coarsely. Set aside.
For pineapple caramel, place brown sugar and half cup water in a saucepan and bring to the boil. Simmer til syrupy, about 5 minutes. Add diced pineapple, ginger, and rum and simmer for 5 minutes. Stand to cool.
Thread prawns, Broccolini®and pineapple cubes onto skewers. Drizzle with pineapple caramel and sprinkle with nut crumble.