1-2 medium-hot red chillies, deseeded and finely chopped
225-275g cherry tomatoes, halved
How to make Sweet and sour chilli prawns:
De-vein the prawns if necessary, by inserting a cocktail stick into their backs about halfway along and hooking out the thin black vein with the tip.
Cut the green tops from the spring onions and cut them lengthways into thin shreds. Set aside for a garnish. Thinly slice the white parts of the spring onions on the diagonal. Mix the chilli sauce, ketchup, sugar, soy sauce and vinegar together in a small bowl.
Heat half the oil in a wok or large, deep frying pan. Add the ginger and cook for 30 seconds, then add the prawns and stir-fry for 2 minutes or until the prawns are just cooked through. Transfer them to a plate.
Mix the cornflour with 1 tablespoon of cold water. Return the wok or pan to the heat and add the remaining oil and the garlic and chilli. As soon as they start to sizzle, add the white spring onion slices and cherry tomatoes and stir-fry for 30 seconds. Add the chilli sauce mixture and the cornflour mixture and simmer for a few seconds until thickened and smooth. Return the prawns to the wok with the shredded green spring onion and toss everything together well. Serve with noodles or steamed white rice.