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).
if you don t have access to a grill though heat olive oil in a pan until nearly smoking sear the steak on both sides until very brown transfer to an oven proof pan add your mushrooms place a pat of butter on top of the meat and bake at 425 for about 10 minutes to finishthis would be for a steak at least an inch thick if it s less than that then searing in the pan is really all you ll need to doransfer to an oven proof pan add your mushrooms place a pat of butter on top of the meat and bake at 425 for about 10 minutes to finish this would be for a steak at least an inch thick