In a small bowl, combine minced garlic, chopped rosemary, chopped thyme, olive oil, salt, and black pepper to create the marinade.

Rub the marinade all over the crown roast of lamb, ensuring it is well coated. Cover and refrigerate for at least 2 hours, preferably overnight.

Preheat your oven to 375°F (190°C).

Place the marinated lamb in a roasting pan and roast in the preheated oven for about 90 minutes, or until the internal temperature reaches 145°F (63°C) for medium-rare.

Remove the lamb from the oven and let it rest for 15 minutes before carving. Garnish with fresh rosemary and thyme sprigs before serving.