Preheat oven to 425°F (220°C). Pat roast dry with paper towel and season with crushed peppercorns and salt. Transfer to roasting pan fitted with rack. Cook roast 30 min. Reduce temperature to 300°F (150°C). Add shallots and garlic to roasting pan. Roast 2 to 2 1/2 hr., until thermometer inserted in centre registers 145°F (63°C) for medium-rare. Transfer roast to cutting board. Cover loosely with foil and rest 25 to 30 min.
Meanwhile remove garlic from pan. Squeeze out garlic cloves into bowl (discard skins). Set aside. Skim excess fat from roasting pan. Transfer pan, with shallots, to stove top over medium heat. Stir broth and wine into pan drippings and shallots. Bring to a boil. Stir in garlic. Simmer until sauce reduces by half. Transfer to blender and puree until smooth.
Slice roast and serve with gravy.