• Buy a Prime-grade rib roast. While we use the term "prime rib" as a generic term to describe any rib roast, that is incorrect unless the meat is officially graded USDA Prime. This is the highest grade available, which virtually guarantees tender, well-aged, flavorful meat. It is expensive and only found at the finest butchers, but for Christmas dinner, get the best. Most supermarket beef is graded Choice, which can be excellent, but it is aged differently than Prime, and has less fat (and in beef, fat equals flavor).

• The rib section of a steer has twelve ribs, but home cooks rarely serve a whole twelve-rib roast. Try to buy a roast from the "small end" of the rib section, as it will have less fat and more meat to the pound. To serve eight to ten people, buy a 4- rib roast. For smaller or larger roasts, just use the timing estimates below. If you are having a small crowd, still buy a 3-rib rib roast, as 2-rib roasts are hard to roast evenly.

• Some rib roasts are sold with the thick fat cap on top of the meat intact, and some are trimmed. I prefer to have most of the fat cap intact and trim it myself to a 1/8- to 1/4-inch thickness, if necessary, In any case, some meat will be exposed. If you trim away a good amount of fat, the purchased weight of the roast will be reduced, so adjust your cooking time as needed. While a kitchen scale is the best way to weigh the meat, of course, you can simply estimate the difference.

• After the grade of the meat, timing is the next most important thing to keep in mind. Check the internal temperature with a good instant-read or digital thermometer. Be sure to remove the roast from the oven 10°F before it reaches the desired internal temperature! The residual heat in the roast will continue to cook the meat, even outside of the oven. So, if you want medium-rare meat at 130°F, remove the roast when the thermometer reaches 120°F (or even few degrees lower, if you are a rare meat fan). If you and your guests prefer medium meat, at 140°F, remove the roast when it reaches 130°F. It is a waste of money to cook a rib roast beyond 140°F because the rich, beefy flavor isn't there. If you have a "well-done" person, serve them the end cuts, or place their sliced meat back in the oven for a few minutes (or microwave it until it looks like the way they want it).

• My perfect roast beef has a tasty, crisply browned crust and a juicy interior. For rib roast of any size, follow this roasting time estimate. Place the roast in a preheated 450°F oven and roast for 15 minutes. Reduce the heat to 350°F and continue roasting until done. Allow about 15 minutes per pound for medium-rare meat, and 17 minutes per pound for medium (calculate the time from when the roast goes in the oven, not from when the temperature is reduced). During the last 30 minutes of roasting time, be sure to check the roast's internal temperature occasionally to avoid overdone meat.

• "Au jus" sauce is nothing more than beef stock stirred into the degreased roasting pan and brought to a boil. It is not thick like a typical sauce or gravy. The au jus will only be as good as your stock, so I strongly recommend that you use homemade beef stock. If you must use canned stock, buy the best you can find, but forget about using salty, artificially-flavored bouillon cubes.

One 4-rib standing beef rib roast, preferably Prime grade (about 8 pounds)
2 large garlic cloves, peeled
1 1/2 teaspoons salt
1 teaspoon dried thyme
1 teaspoon dried rosemary, crumbled
1/2 teaspoon freshly ground black pepper
3 cups beef stock, homemade highly preferred, or use low-sodium canned beef broth

Sour Cream Horseradish Sauce (recipe follows), optional

1. Position a rack in the lower third of the oven and thoroughly preheat to 450°F.

2. Using a sharp thin knife, trim any fat on the top of the roast to 1/4-inch thickness. Using a large knife, finely chop the garlic on a work surface. Sprinkle with 1/2 teaspoon of the salt and mash and smear the garlic on the work surface to make a paste. Scrape into a small bowl. Add the remaining 1 teaspoon salt, and the pepper, thyme, rosemary, and pepper. Rub the seasoning mixture all over the roast, including the underside.

3. Place the rib roast, meaty side up, in a large roasting pan. (No need for a roasting rack, as the bones create a natural one.) Roast for 15 minutes. Reduce the oven temperature to 350°F. (Do not open the oven door.) Continue roasting until an instant-read thermometer inserted in the center of the roast reads 115° to 120°F, about 2 hours total roasting time for medium-rare meat. For an accurate reading, be sure the tip of the thermometer is positioned in the center of the meat. Transfer the roast to a carving board. Let stand for 20 minutes.

4. While the meat is standing, make the "au jus" sauce: Pour out all of the fat from the roasting pan and discard (or reserve if making Yorkshire puddings). Place the roasting pan on two burners on medium heat. Add the beef stock and stir to release any browned bits in the pan. Bring to a boil and cook until the stock is slightly reduced, about 2 minutes. Transfer to a gravy boat.

5. To carve the roast, using a meat fork and a long thin carving knife, stand the roast on the its meaty end. In one piece, carve off the rib section, and set aside Slice the meat, cut the ribs into individual pieces, and serve immediately, with a spoonful of the au jus sauce poured over each serving. Pass the horseradish sauce on the side, if desired.