01 - Remove beef from refrigerator 30 minutes prior to cooking. Preheat oven to 400°F (gas mark 6).
02 - Combine olive oil, Dijon mustard, parsley, rosemary, thyme, garlic, salt, and pepper in a small bowl to form a paste.
03 - Pat beef dry with paper towels. Arrange onion, carrots, and celery in roasting tin to create a vegetable trivet. Place beef on top.
04 - Rub herb paste thoroughly over beef, pressing to adhere evenly.
05 - Roast beef at 400°F for 20 minutes.
06 - Reduce oven temperature to 350°F (gas mark 4). Roast for approximately 1 hour 10 minutes more, or until internal temperature reaches 130°F for medium-rare or 140°F for medium doneness.
07 - Remove from oven and cover loosely with foil. Allow beef to rest for at least 20 minutes.
08 - Slice beef and serve with pan juices and roasted vegetables as desired.