Preheat the oven to 450 degrees F. Place the roast in a roasting pan. Brush with the mustard; sprinkle with rosemary, salt and pepper. Roast 20 minutes; reduce oven temperature to 325 degrees F. Roast to desired doneness; allow 20 minutes per pound - total cooking time - for rare, 25 for medium rare and 30 for well done. While the beef cooks, heat the oil in a pot over medium heat. Add the shallots and cook until tender, about 3 minutes. Add the wine and reduce by half. Whisk the stock and flour together in a bowl, add to the pot. Bring to a simmer and cook until lightly thickened; remove from the heat. Transfer the cooked roast to a plate; tent with foil and rest 10 minutes before carving. Drain the fat from the pan and set on the stovetop over medium-high. Pour in the sauce and simmer 5 minutes. Serve the sauce in a gravy boat alongside the roast.