Madras Fish Curry 

1 onion, coarsely chopped

3-4 garlic cloves, coarsely chopped

2.5 cm (1 in) piece of fresh root ginger, chopped

2 tablespoons red wine vinegar

4 tablespoons olive or groundnut oil       

¼ teaspoon cumin seeds

¼ teaspoon fennel seeds

12 fenugreek seeds

½ teaspoon ground coriander

½ teaspoon ground cumin

¼ teaspoon ground turmeric

2 canned tomatoes, finely chopped

½ teaspoon cayenne pepper, or more to taste 1 teaspoon garam masala

¾ -1 teaspoon salt

200 ml (7 fl oz) water

675 g (1 ½ lb) fish Freshly ground black pepper 

Note: try  thick, skinned fillets of mackerel, bluefish, haddock, sea bass or salmon, cut into 7.5 cm (3 in) chunks, or king fish or swordfish steaks.   

Put the onion, garlic, ginger and vinegar in a blender or food processor and blend to a smooth paste.  Put the oil into  a large, wide pan, preferably non-stick, and set it over a medium high heat.  When it is very hot, put in the cumin, fennel and fenugreek seeds and let them sizzle for 5 seconds.   Quickly pour in the paste from the blender, using a rubber spatula to get it all out.  Stir and fry it for 10-15 minutes, until it is golden brown.   Add the ground coriander, cumin and turmeric and stir for a minute.  Add the tomatoes, cayenne, garam masala, salt and lots of black pepper.  Cook, stirring, for another 2-3 minutes. Stir in the water and bring to the boil.  Cover the pan, reduce the heat to low and simmer very gently for 30 minutes.   Add the fish in a single layer.  Simmer gently, spooning the sauce over the fish, until it has just cooked through.