Preheat the oven to 425°F (218°C).
Combine the minced garlic, rosemary, thyme, parsley, 1 teaspoon salt, 1/2 teaspoon pepper, and 2 tablespoons of olive oil in a small mixing bowl to create a herb paste.
Pat the beef roast dry with paper towels and coat the surface evenly with Dijon mustard.
Press the herb paste onto the exterior of the beef roast until well-coated.
In a separate bowl, toss the halved baby potatoes with the remaining olive oil, salt, and pepper.
Place the beef on a rack in a roasting pan and arrange the potatoes around the base.
Roast for 45 to 60 minutes, or until the internal temperature of the beef reaches 135°F (57°C) for medium-rare.
Transfer the beef to a cutting board and allow it to rest for 15 minutes before carving. If necessary, keep potatoes in the oven during this time to achieve desired crispness.