Got this from America's Test Kitchen, have used it, and find that it
makes the best prime rib I have ever had.

I age it for 7 days. Also, I cut the meat off the rib and THEN TIE IT
BACK ONTO THE BONES before I roast it. This way it holds up well and
is easier to slice before serving.

Buy the ribs that are the 10,11, and 12th ribs as they are not a fatty
but still fatty enough.

Why this recipe works:

Most of us cook prime rib only once a year, if that, and don’t want to
risk experimenting with the cooking method—especially when the results
are no better than mediocre. We thought that a special-occasion roast
deserved better and wanted to find the best way to get the juicy,
tender, rosy meat that prime rib should have. The principal question
for roasting prime rib was oven temperature, and our research turned
up a wide range of recommendations. Most delivered meat that was
well-done on the outside but increasingly rare toward the center—not
too bad, but not exactly great. Surprisingly, the roast we cooked at a
temperature of only 250 degrees was rosy from the center all the way
out. Additionally, it retained more juice than a roast cooked at a
higher temperature, and the internal temperature rose less during
resting, so we had more control over the final degree of doneness.
Searing before roasting gave us a crusty brown exterior. For
seasoning, prime rib needs nothing more than salt and pepper. Now that
we’d found a dependable cooking method, we could serve this
once-a-year roast with confidence. (less)


For a roast that's as pink, juicy, and tender at the surface as it is
in the center, sear it first, then roast it long and low.


Serves 6 to 8


Remember, even a day or two of aging in the refrigerator will help.

Ingredients

1 first-cut beef rib roast , 3 ribs (about 7 pounds), set at room
temperature for 3 hours, tied twice between the rib bones (see
illustration below)
Salt and ground black pepper

Instructions

1. Adjust oven rack to low position and heat oven to 200 degrees. Heat
large roasting pan over two burners set at medium-high heat. Place
roast in hot pan and cook on all sides until nicely browned and about
1/2 cup fat has rendered, 6 to 8 minutes.


2. Remove roast from pan. Set wire rack in pan, then set roast on
rack. Generously season with salt and pepper.


3. Place roast in oven and roast until meat registers 130 degrees (for
medium-rare), about 3 1/2 hours (or about 30 minutes per pound). Let
stand 20 minutes (a bit longer is fine) before serving.


4. Transfer to cutting board and carve in accordance with the
instructions below.


Technique
Tying and Carving the Prime Rib

1. To carve, remove the twine and set the roast on a cutting board,
rib bones perpendicular to the board. Using a carving fork to hold the
roast in place, cut along the rib bones to sever the meat from the
bones.


2. Set the roast cut side down; carve the meat across the grain into
thick slices.


We didn't tie the first few prime ribs that we roasted. We found out
pretty quickly, though, that unless the roast was tied, the outer
layer of meat pulled away from the rib-eye muscle, causing the roast
to look a little unattractive. Separated from the main roast, this
outer flap of meat also tended to overcook. To solve this problem
easily, tie the roast at both ends running parallel to the bone.

It is a solemn thought: dead, the noblest man's meat is inferior to pork.
- More Maxims of Mark, Johnson, 1927
Mark Twain

Gene