Carefully cut a slit along the back of each prawn and remove the digestive tract, rinse under cold water, drain on kitchen paper and set to one side.
Place your wok over a medium to high heat and once smoking add the oil, diced onion and red pepper, stir fry for 2 minutes and then add the king prawns. After 2 minutes, add the pre-cooked rice, breaking down any clumps using the back of your spoon or spatula whilst remembering to keep tossing the rice in the wok for 3 minutes. Next sprinkle in the curry powder, salt and pepper, continuing to toss the rice and mixing the ingredients well, cooking for a further 3-4 minutes.
N.B: Throughout the cooking time you should be able to hear the rice and ingredients frying; if not, turn up the heat and leave the pan alone until you can see the ingredients jumping in the pan and hear it sizzling away.
Once the rice is completely heated through, sprinkle in the soy sauce and mix well. Switch off the heat and serve.