2 tsp Turmeric
1 tsp Salt
1 kg (2 lb) Firm white fish fillets, skinned, boned and cubed
50 ml (2 fl oz) 1/4 cup Vegetable oil
2 Medium onions, sliced
1 tsp Hot chilli powder
1 tsp Sugar
2 tsp Garam masala
1 Tbs Ground coriander
1/2 kg (1 lb) Tomatoes, blanched, peeled, seeded and chopped
2 Tbs Sour cream
1 Tbs Lemon juice
4 Green chillis, slit in half lengthways and seeded