Heat a wok over a high heat and add the oil. When hot, add the onion, ginger and green chilli and stir-fry for 2–3 minutes, or until the onion starts to turn golden.
Rub the curry leaves between your hands so that they break up and scatter them over the onion. Add the prawns, turmeric, lemon juice and 2 tablespoons water and season with a pinch of salt. Continu