Preheat oven to 450 degrees F. (Oven rack in the center)
Allow rack of lamb to come to room temperature and season with pepper. Heat 2 tablespoons olive oil in a large oven proof skillet. Sear rack of lamb on all sides for 2 minutes on each side. While lamb is browning, combine bread crumbs, garlic, rosemary and ¼ teaspoon pepper. Add 2 tablespoons olive oil to moisten the mixture.
Remove lamb from heat and brush with the Dijon mustard. Roll in the bread crumb mixture until evenly coated. Arrange the rack bone side down in the pan and roast in the preheated oven for 12 to 18 minutes depending on the degree of doneness desired. With a meat thermometer, take a read in the center of the meat after 10 minutes. (140 degrees for rare). Once the desired temperature has been obtained, remove the lamb from the oven and let rest for 5-7 minutes before carving between the ribs.
Note: The internal temperature of the lamb will rise slightly once removed from the oven. Rare to medium rare is the desired temperature for this recipe.