Butterflied leg of lamb has been cut open and unfolded like a butterfly, hence the name. It is an easy dish to prepare in the oven and takes little time and effort. Cooking a butterflied leg of lamb allows you to marinate the meat directly after slicing, resulting in a stronger flavour. This recipe utilises a 7-to-8 lb. boneless leg of lamb, and will serve 6 to 8 people.
Combine 6 tbsp extra virgin olive oil, 4 tbsp lemon juice, 4 crushed garlic cloves and 2 tsp dried rosemary in a large resealable plastic bag. Place the leg of lamb into the bag and seal. Place the bag into the refrigerator overnight to marinate. Turn the bag over several times during this time to coat the leg of lamb thoroughly.
Turn on the grill and allow it to heat for 5 to 10 minutes. Remove the leg of lamb from the bag and carefully pat dry with a clean hand towel. Do not throw away the marinade in the bag. Line a baking pan with aluminium foil and place the leg onto the pan.
Allow the leg of lamb to broil for 5 minutes, and then flip it over. Allow it to cook for 5 more minutes. Remove the leg from the grill and baste it with the extra marinade from the bag.
Preheat an oven to 93.3 degrees C, and then place the leg of lamb into the oven. Insert a meat thermometer into the leg and allow it to cook until the thermometer reaches 51.7 degrees C for rare and 54.4 degrees C for medium-well done. Baste the leg of lamb with the marinade at least twice during the cooking process.
Remove the leg of lamb from the oven and place on a cutting board. Use a sharp knife to carve several long, slanted slices against the grain of the lamb, creating a butterfly wing effect. Baste the butterflied leg of lamb with the marinade a final time, and serve.
The leg of lamb can also be seared using a barbecue grill if a grill is not available. Heat the grill and cook the leg of lamb for several minutes on each side, until the searing is complete. A homemade or commercially purchased marinade may also be used
Never eat a leg of lamb that hasn't been cooked to at least 125 degrees F. The meat will be undercooked and may cause you to get sick.