Rub surface with butter or oil and herbs (rosemary) and let meat come to room temperature for about 3 hours before putting it in the oven. Prehead oven to 450, then cook 4 to 5 pound roast for 20 minutes, total. Turn oven down to 175°F until meat thermometer reads 125 for very rare. Remove from oven and let rest for at least 15 minutes.