The delicacy of lamb or veal sweetbreads is a perfect partner to shellfish, especially in a curry like this. You can use either, but lamb sweetbreads are much better value. You can also replace the prawns with lobster or scampi tails, depending on how extravagant you are feeling.
4tbsp vegetable or corn oil, or ghee
2tsp fenugreek seeds
1tsp fennel seeds
1tbsp fenugreek leaves
1tsp cumin seeds
½tsp caraway seeds
1tsp nigella seeds
1tsp mustard seeds
The black seeds from 10 cardamom pods
2tsp ground cumin
2 medium red onions, peeled and finely chopped
3 medium cloves of garlic, peeled and crushed
A small piece of root ginger, scraped and finely grated
A good pinch of saffron
½tbsp tomato purée
500ml beef or chicken stock
A handful of curry leaves
3 tomatoes, roughly chopped
200-250g plump lambs' sweetbreads, trimmed of any sinew
16 or so large raw prawns, peeled
Salt and freshly ground black pepper
A handful of coriander, roughly chopped, and some more leaves to garnish
Heat 3 tablespoons of the vegetable oil in a heavy frying pan, add the dry curry spices, and cook on a low heat for a minute or so, stirring as they are cooking. Add the onion, garlic, ginger, saffron and curry leaves and continue cooking on a low heat for 3-4 minutes, with a lid on, until soft. Add the tomato purée and stir well, then add the stock, bring to the boil and simmer for 20 minutes. Blend one third of the sauce in a liquidiser, until smooth, then return to the pan.
Meanwhile, season the sweetbreads, heat the rest of the vegetable oil in a frying pan and sauté them on a high heat for a few minutes, turning them as they are cooking until they are nicely coloured. Add them to the sauce and simmer gently for 20 minutes.
Cut a slit down the back of the prawns, a few millimetres deep, and give them a good wash and remove the dark vein, then add to the sauce and simmer for another 5 minutes.
Add the coriander and simmer for another couple of minutes; remove from the heat. Serve with basmati rice and scatter with the sprigs of coriander.