Preheat oven to 400° F. Heat heavy large ovenproof skillet over high hea= t. Add lamb to skillet and cook until brown, turning occasionally, about 7= minutes. Remove lamb from skillet; cool slightly. Spread mustard evenly = over lamb. Combine breadcrumbs, garlic, rosemary and thyme in bowl. Press breadcrumb mixture onto lamb. = Season lamb with salt and pepper. Return to skillet and roast in oven unti= l desired doneness, about 35 minutes for medium-rare.
Transfer lamb to cutting board. Pour fat from skillet. Add broth to skill= et; bring to boil, scraping up any browned bits. Boil until reduced to 1/2= cup, about 2minutes. Whisk in butter. Slice lamb into chops. Divide cho= ps among 4 plates. Pour sauce over. Drizzle pesto over and serve.