750 g (1 lb 10 oz) skinless haddock fillets, boned and cut into chunks
1 tablespoon tamarind paste
4 tablespoons rice wine vinegar
2 tablespoons cumin seeds
1 teaspoon ground turmeric
2 teaspoons hot curry powder
1 teaspoon salt
4 tablespoons sunflower oil
1 onion, finely chopped
3 garlic cloves, finely grated
2 teaspoons grated fresh root ginger
2 teaspoons black mustard seeds or nigella seeds (black onion seeds)
600 g (1 lb 5 oz) canned chopped tomatoes
1 teaspoon caster sugar
200 g (7 oz) cherry tomatoes
chopped coriander, to garnish
steamed basmati rice (optional)
Put the fish in a shallow non-reactive bowl. Mix together the tamarind, vinegar, cumin seeds, turmeric, curry powder and salt in a small bowl. Spoon over the fish and toss to coat evenly, then cover and leave to marinate.
Meanwhile, heat the oil in a large wok or frying pan over a high heat until hot, add the onion, garlic, ginger and mustard or nigella seeds, then reduce the heat to medium and stir-fry for 1–2 minutes.
Add the chopped tomatoes and sugar, stir through and bring to the boil. Reduce the heat again, cover and cook gently, stirring occasionally, for 15–20 minutes.
Add the cherry tomatoes and the fish with its marinade and stir gently to mix. Cover and simmer gently for 5–6 minutes or until the fish is cooked through and flakes easily.
Ladle into warm bowls, scatter with chopped coriander and serve with poppadums and steamed basmati rice, if liked.