Melissa’s butterfly leg of lamb with yogurt & herb sauce

Toast the cumin and coriander seeds over a medium heat in a dry pan for about 2 minutes. Let them cool, then put them in a food processor with all the other ingredients except the lamb and blitz until smooth. Put the lamb in a dish with the marinade and leave in the fridge for about 6 hours.

Preheat the oven to 220°C, gas mark 7. Lift the lamb out of the marinade, shaking off any excess liquid (discard the marinade after use). Spread it out in a roasting tin, fatty side up, then roast for 15 minutes.

Reduce the oven to 190°C, gas mark 5 and cook the meat for another 15 minutes, ensuring all surfaces are thoroughly cooked and nicely browned. The lamb will be pink inside, or medium rare. If you want it more well done, then increase the cooking time by 5-10 minutes. Cover with foil and leave to rest for 15-20 minutes.

To make the sauce, just put everything in the food processor and blend. Taste for seasoning. Slice the meat and arrange it on a warm platter, spooning over any juices that have come out of it, and scatter mint, coriander and some salt on top. Serve immediately, with lime wedges on the side, and the sauce.