To make the sauce, mix together the oyster sauce, kecap manis, soy sauce, chilli paste and sugar.
Heat a wok until just smoking. Add half the vegetable oil and, when hot, stir-fry the prawns until coloured on both sides, then remove.
Heat the remaining oil in the wok and stir-fry the garlic and chillies until fragrant. Add the corn, carrot, cabbage and peas, and