Allow roast to stand at room temperature for at least 1 hour.
Preheat the oven to 375 degrees F. Combine the salt, pepper and garlic powder in a small cup. Place the roast on a rack in a roasting pan. Rub the seasoning onto the roast. Insert the temperature probe into the meat. These probes are vital to this cooking method to determine how long to leave the roast in the oven. This $20 tool will nearly guarantee amazing eating results every time.
Roast for 1 hour in the preheated oven. Turn the oven off and leave the roast inside. Do not open the door. Leave it in there for anywhere from 30 minutes to 3 hours, until the probe in the roast reaches 128 degrees from rare to medium-rare. Remove from the oven and tent with foil and let rest a full 30 minutes. If dinner is to take place more than 60 minutes after removing from the oven, then preheat the oven again to 375 degrees F. and plan to put the roast back into the oven for about 30 minutes before serving. The internal temperature should be at around 140-145 degrees F. The ends will usually be closer to well-done and gradually move toward rare or medium-rare in the center. Remove from the oven and let rest for 10 minutes before carving into servings.