How to Make It
Preheat oven to 425°F. Let beef stand at room temperature for at least 10 minutes or up to 1 hour. Rub with 1 tablespoon oil and season with 1¼ teaspoons salt and ￼½ teaspoon pepper; place on a rimmed baking sheet.
Toss brussels sprouts and shallots with 1 tablespoon oil and remaining ¾ teaspoon salt and ½￼ teaspoon pepper. Arrange around beef. Roast until vegetables are slightly tender, 12 to 15 minutes. Increase temperature to broil.
Broil, turning beef every 2 to 3 minutes, until vegetables are lightly charred and beef reaches an internal temperature of 128°F to 130°F for medium rare, 10 to 12 minutes. Remove from oven. Loosely tent with foil. Let rest for at least 10 minutes before slicing.
Whisk together mustard, vinegar, Worcestershire, syrup, and remaining 1 tablespoon oil. Drizzle over beef and vegetables.