1. shell prawns with sharp knife. Using sharp point of knife, cut each prawn down the back and remove black vein. With the knife, make a deep slit down the back of the prawn (not your finger), take care not to cut right through. Combine marinade ingredients in bowl (all with marinade sign plus the last 3 items in ingredients. Add prawns, mix well and let stand for 2 hours. 2. peel onions, cut in half, then cut each half in wedges. 3. Heat oil in large pan or wok, add onions, saute until transparent, approx 2 minutes. 4. Add prawns and marinade to wok and saute until prawns turn light pink or in other works, cooked. That should take 3 minutes or a bit longer. Add water and mix well. Arrange lettuce around the edge of the plate. Spoon prawns on the lettuce. To serve intraditional style, place a small metal bowl containing brandy. Light the Brandy and pick up a prawn with chopsticks or any other non flamable material and hold the prawn over the flame to heat and add flavor to the prawns (also to barbeque it in a sense).