Mutton is meat from a sheep more than two years old that has a stronger flavor compared with lamb. The preparation of mutton requires vigilance, because overcooking it will ruin the texture. Mutton is a less tender cut of meat compared with succulent lamb. When cooked well, it conveys an equally pleasurable texture, but it tends to be more challenging to achieve this result. Slow roasting the meat and salting it prior to roasting are particular steps that yield a more successful flavor.
Apply salt to the entire external area of the mutton roast. Allow it to stand for at least an hour and less than two hours at room temperature. Preheat the oven to 225 degrees F. Apply pepper to the mutton roast's outer area.
Wrap the mutton roast with kitchen twine until its surface area is reasonably symmetrical to improve its uniform roasting potential. Add olive oil to a skillet and heat on high. Brown the mutton roast for approximately three minutes on all sides.
Place the mutton roast on a roasting rack in a roasting pan. Insert the tip of a meat thermometer into the thickest area of the mutton roast to ensure an accurate reading. Place the roast into the oven and heat for approximately one and a half hours until the thermometer reads 115 degrees F. Turn off the oven. Allow the roast to remain in the oven for approximately 45 minutes, until the thermometer reads 130 degrees F.
Remove the roast from the oven and allow to stand for approximately 10 minutes, until the juices redistribute. Place the roast on a cutting board and cut against the grain into thin slices.