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 the lamb, place the lamb steak into a bowl, rub with the olive oil and season with salt and freshly ground black pepper. Heat a griddle pan and chargrill the steak for 5-6 minutes on each side, or until cooked to your liking. Leave to rest for five minutes.
Place the lamb in a roasting or sheet pan with the ribs curving down, and coat the tops with the mustard mixture. Allow to stand for 1 hour at room temperature. Preheat the oven to 450 degrees F. Roast the lamb for exactly 20 minutes for rare or 25 minutes for medium-rare.Remove from the oven and cover with aluminum foil. Allow to sit for 15 minutes, then cut into individual ribs and serve. Note: Frenching refers to scraping the meat off the tips of the bones.reheat the oven to 450 degrees F. Roast the lamb for exactly 20 minutes for rare or 25 minutes for medium-rare. Remove from the oven and cover with aluminum foil. Allow to sit for 15 minutes, then cut into individual ribs and serve. Note: Frenching refers to scraping the meat off the tips of the bones.