Preheat oven to 325 degrees F.

Rub roast with 3 cloves minced garlic, 1 teaspoon rosemary, 1 teaspoon oregano, 1 teaspoon thyme, and 1 tablespoon oil. Season with a generous sprinkling of salt and pepper. Let sit for 30 minutes.

Heat 1 tablespoon oil in saute pan over high heat. Add roast and sear on all sides. Place on roasting rack and roast in the oven until internal temperature is 140 degrees F, about 1 hour 45 minutes - 2 hours. Remove from oven and let rest 20 minutes before slicing. Reserve the juices and set them aside.

Prepare the spicy mustard. Mix 2 tablespoon dijon mustard with 2 tablespoon spicy brown mustard and 2 tablespoon creamed horseradish. Set aside.

Meanwhile, make the au jus. Melt 2 tablespoon butter in a shallow skillet over medium heat. Add the minced shallots and saute for 2 minutes, stirring frequently. Whisk in 1 tablespoon flour and cook for 1 minute. Add 2 tablespoon sherry and bring to a boil, cooking out the alcohol for about 1 minute. Add 14 ounces of beef broth and the reserved beef juices. Bring to a simmer over low heat and cook for 5 minutes.

Dip the rolls one at a time in the au jus. Stuff with thinly sliced roast beef. Serve with spicy mustard on the side.