How long does it take to cook a leg of lamb?
As always, there are many different recipes for cooking a leg of lamb. Elise cooks her leg of lamb with the bone in by starting at 425 degrees for 20 minutes then turns the oven down to 300Â°F and continues to roast the meat for about 10-12 minutes per pound for medium rare lamb.emove the lamb from the refrigerator at least 1 hour before cooking it. Preheat the oven to 450 F. degrees. (450Âº F = 230Âº C = gas mark 9). Snip the corner of the bag and squeeze the marinade out into the sink.