PRIME RIB Serves 4-12. 4-8 lb rib roast, about 4-6 bones, from the "small end" kosher salt Let roast come to room temperature on the counter, 2-3 hours. If the roast is 5lbs or less: Heat oven to 225F degrees. Heat a large skillet over high heat. Sear roast on all sides, about 2 minutes a side. Place roast in oven on a roasting pan. Continue below. For roasts over 5lbs: Heat oven to 500F degrees. Rub roast with kosher salt. Place in oven in a roasting pan, and reduce temperature to 250 after 5 minutes. Monitor temperature with a meat or instant-read thermometer. Expect about 20-30 minutes of roasting per pound. Remove at 130 degrees for rare, 140 for medium rare. Let roast stand for 15-20 minutes, temperature will rise anopther 5-10 degrees.