Directions. 1  Preheat oven to 450 degrees. 2  Season lamb racks with salt and pepper; coat each evenly with 3 Tbsp pesto. 3  Roast on baking sheet until about 5 degrees less than desired doneness (about 20 min for medium). 4  Transfer lamb to clean platter; let rest 10 min before slicing.
Preheat the oven to 400 degrees F. Using your hands, rub the lamb all over with the lemon juice. Pat the garlic and rosemary evenly all over the surface of the meat. Season the meat with the salt and pepper and place the lamb in a roasting pan. Place the lamb in the oven and roast for 30 minutes.
Season meat with salt and pepper. Roast lamb, basting every 20 to 30 minutes, first with the reserved marinade, and then with juices that accumulate in the pan. The lamb will need to cook for about 20 minutes per pound (2 hours for a 6-pound leg of lamb, and 2 hours and 40 minutes for an 8-pound leg of lamb).An instant-read thermometer inserted in the thickest part of the meat, not touching the bone, should read 145Â° when the lamb is medium-rare. 5.nsert thermometer in the thickest part of the meat, not touching fat or bone. Roast in a preheated 325Â° oven for about 25 to 30 minutes per pound, or until meat thermometer registers 150Â° to 175Â°, depending on how well you like it done.