In a large bowl, combine bread crumbs, garlic, rosemary, 1 teaspoon salt and 1/4 teaspoon pepper. Toss in 2 tablespoons olive oil to moisten mixture. Set aside. Season the rack all over with salt and pepper. Heat 2 tablespoons olive oil in a large heavy oven proof skillet over high heat. Sear rack of lamb for 1 to 2 minutes on all sides. Set aside for a few minutes. Brush rack of lamb with the mustard. Roll in the bread crumb mixture until evenly coated.
For oven cooking, place the lamb in an uncovered roasting pan and cook at 165 degrees C (325 degrees F). For every 0.5 cm (inch) of thickness, allow 10 to 15 minutes of cooking time. You can allow more time for a well-done steak, cooking to an internal temperature of 76 degrees C (170 degrees F).
1 Place lamb chops on very hot grill and close lid. This will help chops cook from all angles and sear in juices.  Cook lamb chops with lid down for 3â4 minutes. Flip chops over (at 4 minutes) using grilling tongs. Do not use a fork as it will let out all of the juices you are trying to keep in.