Use a small end rib roast, as it is much higher quality than the large end. The small end is a cut, not a size. It is more evenly marbled and has less fat and gristle. It sometimes is higher in cost, but worth it, and I can’t express this enough. Ask the butcher at the grocery store, as sometimes they keep these in the back. They look considerably different, and a decent butcher will respect your knowledge of the cut!
Let the roast sit at room temperature for 1 hour.
Preheat oven to 350 degrees.
Rub the meat thoroughly with garlic salt and pepper.
Place meat in a shallow pan, fat side up. Cook for one hour. Turn heat off.
Do not open the oven. The roast can be left for 1-5 hours.
Turn oven back onto 350 and cook for 30-40 more minutes.
Remove from oven. Let rest a few minutes before slicing.
Put all ingredients in a small saucepan, bring to a boil.
Reduce to a simmer.
If desired, just before serving, add some of the pan drippings from the prime rib.