Amasi-marinated butterflied lamb with chimichurri sauce

Prepare the lamb

Prepare the lamb the day before you want to cook it. Open up the deboned leg of lamb and lay it flat on a chopping board, skin-side down. Using a sharp knife make an incision halfway into the flesh on each side where the meat is thicker and open it out to look like an open book. This will give you a flat piece of lamb of more or less even thickness.

Prepare the marinade

Mix the amasi with the garlic and herbs and pour into a large ziplock bag. Slide the butterflied lamb into the bag and seal. Massage the bag well to get the marinade into all parts of the meat. Refrigerate for 24 hours (3 hours minimum).  

Remove the meat from the fridge at least 1 hour prior to cooking, so that the lamb comes up to room temperature and cooks evenly. Remove the meat from the ziplock bag and wipe off most of the marinade. Reserve the marinade.

Prepare the basting sauce by mixing the oil, butter, garlic, balsamic and lemon juice together. Season the lamb with salt and pepper. 

Preheat your barbeque/ weber until very hot. Once hot, cook the meat, fat side down for 15 minutes on a side until nicely browned, basting from time to time.  Turn the meat over and cook on the other side. Cook the meat for 40-45 minutes in total, or until medium rare (internal temperature in the thickest part  must register 57°C after resting 62°C) or until required doneness. Transfer the lamb to a warm platter and let it rest for 15 minutes, covered loosely with foil. Slice thinly across the grain. Garnish with grilled lemons and fresh rosemary on the side. 

Prepare the sauce [sauce can be made 1-3 days ahead of serving] 

Combine the red onion, garlic, vinegar, and lemon juice in a small bowl and leave to marinate for 10 minutes. 

Transfer the garlic mixture and liquids to a food processor or blender fitted with a metal blade. Add the parsley, cilantro, oregano, and chili and pulse a couple of times to chop the herbs finely.  

With the motor running add the oil slowly, stop the machine, scrape down the sides and add the coriander, olive oil, salt, and pepper. Pulse to combine. Store in a jar in the refrigerator for later use.  

Note

A meaty sauce can be made by roasting the lamb bones in a hot oven. Place the bones and a quartered onion in a roasting pan, season and roast in a hot an oven 200°C for an hour. Remove the roasted lamb bones from the roasting pan. Pour a cup of hot water or stock into the pan and loosen the roasted bits from the pan add ½ cup of the retained marinade and stir until blended. Season with salt and pepper. Strain the sauce and pour into a gravy boat to serve with the lamb.