01 - Remove beef from refrigerator 30 minutes before cooking to reach room temperature. Preheat oven to 400°F (gas mark 6).
02 - Combine olive oil, Dijon mustard, parsley, rosemary, thyme, garlic, sea salt, and black pepper in a small bowl to form a paste.
03 - Pat beef dry with paper towels. Place sliced onion, carrot chunks, and celery chunks in a roasting pan to create a trivet, then set beef on top.
04 - Rub the herb paste evenly all over the beef, pressing gently to adhere.
05 - Place roasting pan in preheated oven and cook for 20 minutes. Reduce temperature to 350°F (gas mark 4) and continue roasting for approximately 70 minutes, or until meat thermometer reads 130°F for medium-rare or 140°F for medium.
06 - Remove roast from oven, loosely cover with foil, and rest for at least 20 minutes before slicing.
07 - Carve the beef and serve accompanied by pan juices and roasted vegetables.