When life calls for a celebration, prime rib comes to the rescue. The homemade spice rub is delicious on the beef in this elegant entree, but it also complements more affordable cuts of beef, or even pork or chicken.
In a small bowl, combine salt, mustard, black pepper, garlic, onion powder, thyme, oregano, coriander and celery seeds. Set aside 1/4 cup. (Transfer the remaining mixture to a small jar. Store in a cool, dry place for up to 3 months. Stir or shake before using.)
Rub oil over meat. Sprinkle the 1/4 cup spice mixture evenly over meat; rub in with your fingers. Make six 1x1/2-inch knife slits into the fat side (the slits allow the seasoning to penetrate into the meat).* Place meat, fat side up, in a large roasting pan. Insert an oven-going meat thermometer into center, being careful that it doesn't touch the bones.
Roast beef in a 350° oven for 1-3/4 to 2-1/4 hours for medium-rare (135°) or 2-1/4 to 2-3/4 hours for medium (150°).
Transfer meat to a cutting board. Cover with foil and let stand for 15 minutes before carving. (The temperature of the meat will rise 5 to 10 degrees during standing.)
At this point, you can cover the meat loosely with plastic wrap and chill up to 24 hours before roasting.
Perfect! Dry rub an absolute must. Took out 5lb roast at 143 degrees and rested. So delicious!!!