The British loved meat. They loved big, roasted joints, and this recipe is a good example of how the local cooks changed the British approach to such dishes. This makes moist, mildly spiced lamb to be pulled apart.
Make a smooth paste of the marinade ingredients, except the curry leaves, and set aside.
Make about 12 incisions, about 4cm (1 ½ inches) deep, in the meatiest part of the lamb, then put two curry leaves into each incision. Place the lamb into a roasting pan, just large enough to hold the lamb, without too much extra space.
Cover the lamb with the marinade, then work it into the meat and incisions using your hands. Cover the pan with cling film and refrigerate. Allow to marinate overnight.
to cook
Remove the lamb from the refrigerator and allow to come to room temperature.
Preheat oven to 220 °C.
Tuck the onion halves, cut side down, beside the lamb. Drizzle the lamb with the mustard oil and add a cup of the water to the tray, being careful not to wash any marinade off the lamb. Place the pan into the hot oven, uncovered, and cook for 30 minutes.
After 30 minutes, reduce oven to 140 °C. Remove the tray from the oven and gently baste the lamb with the pan juices. Cover the tray, return to oven and cook for a further four hours, or until the meat comes away from the bone. Baste the lamb with pan juices every 30 minutes.
Once cooked, carefully remove lamb from the tray and place on a serving platter (see notes). Cover with foil and a tea-towel, set aside and allow to rest for 15 minutes.
for the gravy
Carefully spoon the fat and oil from the tray into a small saucepan. Do not include any of the marinade ingredients or onion yet.
Heat the saucepan over a medium heat and add the mustard seeds and curry leaves, and fry for one minute, or until the mustard seeds pop. Add the ginger, garlic and chilli slices and fry for two minutes, or until slightly coloured. Add the tomatoes, and fry for a further two minutes to soften.
Add the remainder of the contents of the baking tray – the marinade, onions and pan juices to the saucepan. Using a fork, masher or a hand blender, make the contents as smooth as possible. Add the coconut milk, mix well and bring to simmer.
Add the lemon juice and check the seasoning. Remove from the heat, and place the gravy into a serving jug.
to serve
Uncover the lamb, and using two forks, separate the meat a little.
Sprinkle over the garam masala and coriander leaves. Garnish with the stem of curry leaves.
Serve with the jug of gravy on the side.
notes
A bulb of garlic can also be called a head of garlic. It contains six to eight individual sections called cloves.Removing the cooked lamb from the baking tray requires care, as it might fall apart. We suggest you use a wide, slotted spatula, gently placed under the lamb to lift it out.After adding the contents of the baking tray to the gravy, we use a hand blender to puree it. A more rustic approach is to use the fork or masher as described, which will give a chunkier finish. It is important to break the onion down as much as possible because this is what will thicken the gravy.