Prime rib
Season salt
Celery
Beef soup base
Mushrooms
Garlic powder
Carrots
Onions
Worcestershire sauce

Season rib roast with garlic powder and season salt; refrigerate overnight. Cook covered in 400 degree oven until the internal temperature reaches 120 degrees for rare, 130 degrees for medium or 140 degrease for well done meat (approximately 4 hours). Temperature will continue to rise about 5 to 10 degrees after removed from oven. Let stand 20 minutes encased in fat and bones.

Untie; remove fat and bones. Make au jus by boiling carrots, celery, onion, beef base, garlic powder and Worcestershire sauce, straining and discarding vegetables. Add mushrooms to the au jus.