Remove the roast from the refrigerator 2 hours before roasting. Mince the garlic on a cutting board, add the salt, and using the flat side of the knife, crush the garlic with the salt until it forms a paste. Place in a small bowl, add the rosemary, pepper, and olive oil and combine. Slather the mixture on all sides of the roast, cover loosely with plastic wrap, and let sit until time to roast.

Preheat the oven to 500°F. Place the roast in a roasting pan, bone side down. Roast for 15 minutes then lower the oven temperature to 325°F. Roast for another 2-2¼ hours or until a meat thermometer inserted into the center reaches 125°Ffor medium rare. Since oven temperatures vary, you should start testing the temperature of the meat after it has roasted at 325°F for 1½ hours. Remove from the oven, cover loosely with foil, and let sit for 15-20 minutes before serving.