One of the things I look forward to whenever there is a family celebration is prime rib. Though I have tested many different methods over the years, this version is always perfectly cooked and has that crispy, crunchy crust everyone wants from prime rib, thanks in large part to a heaping helping of ground mustard. —Laura Dembowski
Preheat oven to 450 degrees F. Take rib roast out about 30 minutes prior to cooking to come to room temperature. While warming up, cut tiny slits all over the meat and fat. Insert a slice of garlic into each of the slits. They should be just wide enough and deep enough to hold the slice of garlic. Sprinkle salt, pepper, and dry mustard over all surfaces of the roast. Rub seasoning in with hands.
Place roast in foil lined roasting pan to make clean up easier. Put roast in oven with bones facing the back of the oven. Roast for 15 minutes at 450 degrees F. After those 15 minutes, lower oven temperature to 350 degrees F. Continue cooking roast for 15 minutes a pound, including the initial 15 minutes at 450. For a 6 pound roast, this will be 1 hour 30 minutes total. It is very important to include the 15 minutes at 450. Do not open the oven during the cooking process, as this will let heat out of the oven. You should be able to hear the roast sizzling throughout the cooking process.
When the roast is finished cooking, remove it from the oven. Leave it in the pan to rest for about 15 minutes. During this time you may tent the roast, however, this will cause some of the crust to become soggy. The meat will stay quite hot even if not tented.
Once the roast has rested, move it to a serving platter for slicing. Plan on getting three slices from each bone. Take off only the strings you need to in order to cut it, but do make sure to remove them before serving. If the roast is not done enough, place individual pieces back in the oven on a foil lined baking sheet or roasting pan or simply on foil for a few minutes. Be sure to check it often, as it will get done very quickly.
Roast may be stored in the refrigerator for 3 days. It may be eaten cold, or reheated in a 350 degree F oven for about 15-20 minutes on a foil lined roasting pan. The outside will become brown, but when you cut into a piece, it should still be quite pink. Roast the bones for about 30 minutes at 350 degrees F so the meat and fat render and become crispy.