Preheat your oven to 400°F (200°C).
In a mixing bowl, combine the minced garlic, chopped rosemary, thyme, Dijon mustard, olive oil, salt, and pepper. Mix well to create a paste.
Place the racks of lamb in a roasting pan, meat-side up. Rub the herb paste generously over the meat.
In a separate bowl, mix the breadcrumbs with grated Parmesan cheese. Press this breadcrumb mixture onto the meat, creating an even layer to coat the racks.
Insert a meat thermometer into the thickest part of one of the lamb racks, avoiding the bone.
Roast in the preheated oven for 20-25 minutes for medium-rare, or until the internal temperature reaches 130°F (54°C). Adjust the time for your desired doneness.
Once cooked, remove the lamb from the oven and allow it to rest for 5-10 minutes. This helps the juices redistribute throughout the meat.
Slice the rack into individual chops and serve on a platter.