2 stalks of celery, cut in half
2 carrots, peeled and cut in half, lengthwise
1 onion, cut in half
5 pounds prime rib of beef, bone in
Fresh ground pepper
Preheat oven to 450 degrees
Rub roast liberally with salt and pepper.
Lay celery, carrots and onion on bottom of a roasting pan large enough to hold the roast. Place the roast on top of the vegetable rack. Place in the hot oven and roast for 15 minutes.
Without opening the oven turn the heat down to 300 degrees and continue roasting for 15-20 minutes per pound until a meat thermometer registers 120 degrees in the thickest part of the meat, at least an hour more.
Remove from the oven and pan then place on a cooling rack. Cover with several layers of aluminum foil. The meat will rest and relax and as it does its temperature will rise a bit more to a perfect medium rare.
After at least 20 minutes you may begin carving. Plenty of time to make gravy with the drippings! If the meat is still on the bone simply slice along the bone removing the meat before then slicing it into individual servings.