1Mix the cornflour and 1 tbsp soy sauce, toss in the prawns and set aside for 10 mins. Stir the vinegar, remaining soy sauce, tomato purée, sugar and 2 tbsp water together to make a sauce.
2When you’re ready to cook, heat a large frying pan or wok until very hot, then add 1 tbsp oil. Fry the prawns until they are golden in places and have opened out– then tip them out of the pan.
3Heat the remaining oil and add the peanuts, chillies and water chestnuts. Stir-fry for 2 mins or until the peanuts start to colour, then add the ginger and garlic and fry for 1 more min. Tip in the prawns and sauce and simmer for 2 mins until thickened slightly. Serve with rice.
