Yoghurt-Simmered Fish Curry

I'm not a huge curry fan, but this recipe, from Anjum Anand - I think she must be England's new Nigella Lawson - caught my eye, and instantly became a favourite. It's healthy and so quick to make.

Yoghurt-Simmered Fish Curry, from Anjum Anand's column in The Times, serves 4
2 Ts vegetable oil
1 large onion, finely chopped
2 green chillies, whole (I used one long red chili with most of the seeds and this was spicey enough)
2 ts garlic paste (I pounded 3 garlic cloves in a pestle and mortar)
1 rounded ts ginger paste (I pounded a 1cm piece of ginger in a pestle and mortar)
¾ ts turmeric powder
2 ts coriander powder
20g ground almonds
180ml yoghurt, beaten
1 medium tomato, cut into large pieces
4 x 175g portions of firm white fish fillets (I used bream)

Salt and pepper to taste
¾ ts garam masala
Handful of chopped fresh coriander, stalks and leaves

Heat the oil in a large non-stick frying pan. Add the onion and fry until golden and shrivelled, about 10 minutes. Add the chilli, garlic and ginger and cook for 30 seconds. Add salt, turmeric and coriander powder and stir for another 30 seconds. Add the yoghurt and almonds, over a low heat and stir to incorporate. Add a splash of hot water at the same time. Simmer over a low flame for 10 minutes. If the yoghurt looks grainy, do not worry, turn the heat up and stir, it will come back together. Add tomatoes and cook until softened, about 6 minutes, adding splashes of hot water whenever the pan starts to dry out. Stir in 150ml water and bring to a boil*. Add the fish, bring the heat down, cover and simmer until the fish is tender, about 5 minutes, turning halfway. The gravy should be thick but not clinging to the fish. If the gravy is too watery, remove the fish and boil down the gravy until you have the right consistency.
Sprinkle over the garam masala and coriander and serve.
* I added a little water and a little lite cream for a creamier sauce.