Big and beefy, this luscious cut of meat definitely has a celebratory presence.
Here it partners with porcini mushrooms, which are both rubbed on the roast and incorporated into the sauce.
For the best flavor, look for well-marbled meat.

For roast
For sauce
Cook roast:
Put oven rack in middle position and preheat oven to 450�F. Trim all but a thin layer of fat from roast,
Prepare sauce while meat comes to room temperature and roasts:
While wine reduces, soak porcini in boiling-hot water (2 cups) in a bowl until softened, about 20 minutes.
Add porcini-soaking liquid, demi-glace, and remaining 1 3/4 cups wine to reduced liquid in saucepan and boil,
Slice roast across the grain and serve with sauce on the side.
Makes 8 servings.
1 (4-rib) prime rib roast with ribs (sometimes called standing rib roast; 9 to 10 lb)
1/2 oz (2 tablespoons) dried porcini mushrooms, ground to a powder in a blender
1 tablespoon kosher salt
3/4 teaspoon black pepper
2 small onions (1 left unpeeled and halved lengthwise, and 1 peeled and chopped)
3/4 stick (6 tablespoons) unsalted butter
2/3 cup chopped shallots (about 3 large)
1 carrot, finely chopped
1 celery rib, finely chopped
2 garlic cloves, smashed
1 tablespoon tomato paste
2 sprigs fresh flat-leaf parsley
1 sprig fresh thyme
1 Turkish or 1/2 California bay leaf
4 black peppercorns
1 (750-ml) bottle dry red wine such as a good-quality C�tes du Rh�ne
1/2 oz dried porcini mushrooms
2 cups boiling-hot water
2/3 cup veal demi-glace
1/2 teaspoon salt
Special equipment: an instant-read thermometer
Let roast stand at room temperature 1 hour.
then rub roast all over with porcini powder, salt, and pepper.
Transfer to a rack set in a 13- by 9-inch roasting pan. Roast beef 20 minutes,
then reduce temperature to 350�F and roast until thermometer inserted into center of meat registers 110�F, 1 1/2 to 2 hours more.
Transfer to a large platter and let stand, uncovered, 30 minutes.
(Internal temperature of meat will rise to 130�F for medium-rare.)
Cook halved onion, cut sides down, undisturbed, in 1 tablespoon butter in a 2-quart heavy
nonreactive saucepan over moderate heat until browned well, about 4 minutes.
Add chopped onion, shallots, carrot, celery, garlic, and 2 tablespoons butter and reduce heat to moderately low,
then cook, covered, stirring occasionally, until chopped vegetables are softened, 8 to 10 minutes.
Add tomato paste, herbs, bay leaf, peppercorns, and 2 cups wine and boil, uncovered, over moderately
high heat until liquid is reduced to about 1/4 cup, 25 to 30 minutes.
Pour through a fine-mesh sieve set into another 2-quart heavy saucepan, pressing on and then discarding solids.
Drain porcini in a paper-towel-lined sieve set over a bowl and reserve soaking liquid.
Rinse porcini and pat dry, then finely chop. Set aside.
uncovered, over moderately high heat, skimming off froth occasionally, until reduced to about 2 cups, 20 to 35 minutes.
Stir in reserved porcini, then reduce heat to low and whisk in 1/2 teaspoon salt,
any juices from meat accumulated on platter, and remaining 3 tablespoons butter until incorporated.
� Sauce can be made 2 days ahead and cooled completely, uncovered, then chilled, covered. Reheat before using.
� Stainless steel, glass, and enameled cast iron are nonreactive; avoid pure aluminum and uncoated iron,
which can impart an unpleasant taste and color to recipes with acidic ingredients.