Marinate the prawns in the lemon juice, garlic, cumin and ginger for 1-2 hours. Cook the prawns in a little of the butter or margarine for a few minutes, stirring. Remove from pan with a slotted spoon and set aside.
Add the remaining butter to the prawn juices in the pan. Add the onions and the spinach and reduce on a moderate heat, covered. When partly reduced, crumble in the stock cube and stir.
Add the chilli, nutmeg, creamed coconut and prawns. Mix well and cook for 6-7 minutes, stirring occasionally. This goes well with coconut rice and a side salad.