Question: how long does it take to cook a prime rib at 300 degrees?
Answer: Sear in a very hot oven (450-475 degrees) for 30 minutes, reduce heat to 300 degrees, and cook as follows: Rare- 18-20 minutes per pound, Medium- 25 minutes per pound, Well done- 30 minutes per pound. May be served with Horseradish sauce.