How To Cook A Prime Rib Roast

• While you are shopping, pick up a good digital instant-read meat thermometer if you don't already have one. It's the only sure way to tell when you're roast has achieved a desirable cooked temperature
• It is crucial that you allow the roast to come to room temperature to ensure even-cooking. This means leaving it out for up to two full hours right before roasting.
• No matter what size roast you have, you will start it in a pre-heated 450 degree oven for 15 minutes then reduce the temperature to 325 degrees for the balance of cooking time. Cooking times will vary depending on size of the roast and desired level of doneness. The following chart gives approximate times for to reach "rare" at various sizes.

1. Cooking Time for Rare (120u0b0)
2. (3) Ribs, 7 to 8 lbs. 15 minutes at 450u0b0, Then 1 1/4 to 1 1/2 hours at 325u0b0
3. (4) Ribs, 9 to 10 lbs. 15 minutes at 450u0b0, Then 1 1/2 to 2 hours at 325u0b0
4. (5) Ribs, 11 to 13 lbs. 15 minutes at 450u0b0, Then 2 to 2 1/2 hours at 325u0b0
5. (6) Ribs, 14 to 16 lbs. 15 minutes at 450u0b0 Then, 2 3/4 to 3 hours at 325u0b0
6. (7) Ribs, 16 to 18 lbs. 15 minutes at 450u0b0 Then, 3 to 3 3/4 hours at 325u0b0
7. Every half hour or so, baste the ends of the roast with the drippings. Use your meat thermometer about a half hour before the expected end of the roasting time. Make sure to insert it in the thickest part of the meat, not touching the fat or bone. When the internal temperature reaches 120u0b0, pull it out of the oven and cover with foil. Let the roast sit for twenty to thirty minutes. It will continue to cook during this time, reaching a temperature of about 125u0b0 to 130u0b0. This resting period allows the juices and flavors to permeate the roast.
8. Rare meats measure in at 120u0b0 to 125u0b0 with a bright red center that grows slightly pinkish towards the exterior. Medium rare meats measure between 130u0b0 to 135u0b0 and are characterized by their extremely pink center portion that grows brown towards the exterior. Medium meats have a light pink center, brown outer portions and readings of about 140u0b0 to 145u0b0. Medium well is not pink at all and is achieved at 150u0b0 to 155u0b0. Well done is reached at 160u0b0 and above and is characterized by a uniform brown color.
9. Use a long, sharp knife to carve your roast. Serve with Yorkshire Pudding, Au Jus and Horseradish Sauce. Au Jus is French for "with juice". Place the drippings in small containers for dipping.

while, come, no matter

Taken from www.epicurious.com/recipes/member/views/how-to-cook-a-prime-rib-roast-52013601 (may not work)