Heat oven to 450° F. Place the beef in a roasting pan and rub the oil, cracked pepper, salt, and garlic all over the meat to coat evenly. Place the beef in the oven and roast for about 20 minutes. Turn over and roast another 25 minutes or until an instant-read thermometer inserted in the center of the roast reads 150° F. Remove from oven and let rest, covered, for 10 minutes.
Menu plan: Reserve a quarter of the beef for use with Beef Potpies.
While the beef is cooking, place the potatoes in a large pot and cover with lightly salted water. Bring to a boil over high heat. Cover, reduce heat to low, and simmer until the potatoes are tender, about 15 minutes. Drain.
Menu plan: Reserve 1 cup of potatoes for use for Beef Potpies.
Mash the remaining potatoes with a fork until smooth. Mix in the remaining ingredients.
Thinly slice the remaining beef and serve with the mashed potatoes and Herb Salad.