The most expensive option for diners at Dallas's critically acclaimed Abacus Restaurant is a nine-course tasting menu that goes for a fixed price of $90. One of the menu's main ingredients: fish scraps.

The scraps are leftovers after Abacus cuts up fish into larger a la carte portions. They could be thrown away. Instead, chef Tre Wilcox turns them into culinary gold: minute portions for his tasting menu. The menu, which changes frequently and recently included Kobe beef carpaccio and Alaskan king crab ravioli, yields about a 75 percent gross profit margin, the difference between his menu price and ingredient costs, says Mr. Wilcox. That's compared with a 66 percent margin on his a la carte menu.

Whether it's a prix-fixe meal or a more elaborate tasting menu featuring smaller dishes, the fixed-priced option has become a familiar sight to diners across the country. No longer just at the highest-end restaurants like Charlie Trotter's or the French Laundry, the approach continues to spread, as chefs from small, neighborhood joints to downtown boites see it as a way to spotlight key dishes and showcase their best work. In a sample of top U.S. restaurants, consumer researcher Mintel International Group found that 21 percent offered a tasting menu in this year's second quarter, up from 18 percent a year earlier. In New York, Washington and Los Angeles, more than half of the top 10 Zagat-rated restaurants offer bundled meals for a set price.

Another reason diners are seeing so many of these menus lately is that the fixed-price route often delivers a better gross profit margin to the restaurant. Chefs can buy fewer ingredients for the more limited menus and save money ordering them in bulk. In the kitchen, it can mean fewer staff, fewer stations -- and the chance to use food that might otherwise be thrown out. At the table, revenue becomes plentiful and predictable as customers spend a substantial amount each time they dine.

A close look at the economics of more than a dozen restaurants' fixed-price offerings, as well as interviews with consultants, economists and leading chefs, suggests that contrary to what some diners might think, going for the prix fixe isn't always a bargain. Indeed, these menus can cost 20 percent or more than ordering a la carte.

At Boston's newly acclaimed French spot, the Craigie Street Bistrot, for example, a three-course prix-fixe meal is priced at about $70, while ordering an appetizer, entree and dessert separately adds up to $55. And diners who request the the six-course tasting menu at New York's famed Davidburke & Donatella will pay $85, or 27 percent more than ordering a three-course meal a la carte. The gap becomes much wider for people who typically skip dessert and order only a salad and entree.

Fixed-price menus generally come in two incarnations: the prix-fixe menu and the tasting menu, although chefs sometimes mix the terms. Prix-fixe meals usually offer an appetizer, second course, main course and dessert. Comparably priced tasting menus offer more courses -- often as few as six and as many as 14 -- in smaller, three-bite portions.

Chefs say these presentations allow their guests to savor several courses of their finest -- or most interesting -- cuisine, encouraging them to experiment with less risk. And because fixed-price menus involve multiple dishes, chefs also tend to give diners more leeway on how long they occupy the table.

For Tony Foreman and Cindy Wolf, husband-and-wife restaurateurs in Baltimore, the decision to switch to prix fixe started with cheese. Charleston, which describes its cuisine as low-country with French influence, started with an a la carte menu when it opened in 1997. Mr. Foreman says he soon got bored with the format and wanted to adopt a fancier approach.

He started by adding a cheese course, a personal favorite. He had a cheese tray built, which at first included Brie De Meaux, Morbier and Valencay. Then he began writing a "suggested" menu of whatever his wife thought was best on a particular day, and by 2001, debuted an official prix-fixe option.

Still there were frustrations -- only about a third of their customers were ordering from the prix-fixe menu, Mr. Foreman recalls. He felt they weren't getting the full experience. "It's very much like our home, and I want you to see what we have," Mr. Foreman says. "Maybe some people are there all the time, but some people are there once a year, and it bothers me that maybe you miss this, maybe you miss that."

In July of last year, Charleston made the switch to an entirely prix-fixe restaurant. Now, complete meals range from three to six courses, with prices from $67 to $102. The restaurant also offers a separate six-course seasonal menu for $84, or $124 paired with wines.

While he won't give specific numbers, Mr. Foreman says sales have been slightly higher since Charleston made the switch. Mr. Foreman says he can now consistently count on higher per-patron bills, which in turn, has allowed him to make the place more intimate by decreasing capacity to 94 seats from 128, without sacrificing revenue.

Tony Maws serves several prix-fixe menus at his Boston restaurant, Craigie Street Bistrot. They include a nine-course tasting menu for $95; a three-course "chef's market" menu for around $70; and a three-course "neighborhood" menu for $36. More than half of his customers order from one of the fixed-price menus, Mr. Maws says.

Mr. Maws's is a small operation, employing five cooks and bringing in annual sales of about $1 million. Because he changes his menu daily, he orders a limited amount of ingredients that he's sure he can sell. For his mid-August "chef's market" menu, the 36-year-old chef created a three-course preparation of clams with zucchini noodles; braised, slow-cooked Kobe short ribs; and a fruit crisp topped with walnuts and ice cream. He paid $3.25 for the clam-dish ingredients, $11.50 to prepare the ribs and $2 for the dessert. The menu's price: $73. That's a 77 percent gross profit margin -- not bad for an industry where chefs aim for a margin closer to 60 percent.

Gross margins, of course, don't tell the entire economic story. After covering ingredient costs, restaurants wrestle with labor costs and expensive rents to stay in the black. Net income at most restaurants tops out at around 7 percent of revenue, and often less than that. But the higher gross margins -- and the predictability -- of fixed-price meals gives restaurants a safety cushion. "We'd probably be doing a lot worse without a lot of these menus," Mr. Maws says.

At Abacus in Dallas, Mr. Wilcox says about a quarter of his customers order from his tasting menu. One recent lineup included monkfish with tiger-shrimp dumplings and Kobe beef, which Mr. Wilcox purchases for a cheaper bulk rate of $29.99 a pound instead of a regular price as high as $39.99. Costs of the nine-course menu's items range from less than $2 to $6. All told, producing his August tasting menu -- which also included wood-grilled wild king salmon in a lemon sauce and duck prepared three ways -- cost Mr. Wilcox about $25.50. His customers paid $90.

Though modern diners are accustomed to having many menu options, fixed-price menus were historically the standard approach at most restaurants. At the turn of the century, diners ate whatever the local innkeeper had prepared, for a preset price. The practice was known as "table d'hote," or "table of the host." Hotels offered something closer to today's larger tasting menus, but in more of a bonanza. Menus could contain 400 items, with several choices offered over seven courses.

In the early 1900s, food was considered a money loser; local taverns made most of their money on alcohol. Things changed when Prohibition killed that cash cow and people began traveling more and visiting more restaurants. Customers began to demand choice, and a la carte became the preferred format.

The menu endured, but prix fixe started to make a comeback in the 1970s and 1980s. Fast-food chains eventually introduced "value meals" for a set price -- they became a mainstay by the early 1990s. Traditional prix-fixe and tasting menus began appearing in upscale restaurants with more frequency.

The depressed economy following the Sept. 11, 2001, terrorist attacks led many restaurants to serve prix-fixe menus as a promotion to entice customers. Today, diners who have elevated chefs to celebrity status are more willing to let a chef orchestrate their meal while they enjoy the performance in a sophisticated atmosphere. "Americans are learning rapidly, and they have embraced the notion of the chef being equal in stature to a concert pianist," says Patrick O'Connell, the head chef at the Inn at Little Washington, one of the country's most renowned restaurants.

Susan Wilkofsky, a frequent diner, says she enjoys the $43 three-course prix-fixe menu at Lola, a Dallas restaurant. "It's usually worth the value," she says. She feels she gets a better deal on one of her favorites, foie gras, when it's included on a fixed-price menu.

One way to figure out whether a fixed-price menu is a good deal is to examine the basic ingredients. Salads, pastas, chicken and salmon, for example, are typically wide-margin items that restaurants can sell at a hefty markup -- combined into a set menu, that markup is even more opaque. Also watch for descriptions laden with fancy-sounding ingredients that are relatively inexpensive ("tomato carpaccio" means slices of tomato; "beef daube" is restaurant-speak for stew).

Another potential prix-fixe trap: pricey wine pairings. Nearly all multicourse tasting menus will offer wines with each course, and some are beginning to add cocktail and beer pairings. The glasses will be smaller, and the bill potentially 50 percent higher than it would be without the wine.

And then there are those scraps, like the ones served at Abacus. Tasting menus, which commonly comprise many small plates, are an ideal solution for chefs trying to avoid waste, since the ends of fish and beef don't make sizable entree portions. Chefs may also take the remaining amounts of large vegetable deliveries and place them on a tasting menu, knowing they won't get used otherwise.

These servings may not be the premier cuts or selections, but chefs say they're usually fresh and taste just as good. The end of Abacus's monkfish has the same taste as the rest of the fish, just in a more modest form, says Mr. Wilcox. "We don't want to throw anything away," says the 30-year-old rising star who has been nominated for a James Beard Award. His restaurant posts annual sales of about $1 million. "Most chefs are trained to utilize every bit of food we've got -- to move it, to get it into somebody's mouth."

As with any menu, where the food comes from matters. If dining in New York, for instance, and the restaurant is "bringing in salmon from Norway, I'd rather have a bluefish from Montauk, N.Y.," says Michael Moran, a chef instructor at Florida International University in Miami. He says a 50-mile radius is a good benchmark to ensure food is fresh and not handled too much.

A potentially good sign: tasting menus that bear no resemblance to a la carte offerings. This can mean the chef has taken extra time to prepare a unique creation with fresh ingredients. And in a pinch, don't be afraid to ask for a substitution. Though they don't advertise it, many chefs are willing to switch out items that might be intimidating to some diners.

Some chefs don't regard prix-fixe menus as a total fix. For instance, Messrs. Wilcox and Maws fear that making their establishments price-fixed-only can backfire by driving away patrons who lack time for a leisurely, multicourse meal, or prefer choosing their own menu.

"I think the consumer wants the option of spending what he wants to spend and telling you how much time he wants to spend in the restaurant," says New York chef David Burke, who serves both an a la carte and a tasting menu at one of his restaurants, Davidburke & Donatella. Mr. Burke says he employs the tasting menu to showcase his work -- and provide a revenue cushion. It costs him about $35 to serve one of the five-course meals, for which he charges $85 a head.

Mr. O'Connell, the chef of the Inn at Little Washington in Northern Virginia, says he used to serve an a la carte menu, but decided to convert to an all-prix-fixe format in 1987 after he noticed too many customers nibbling at salads while other patrons who might have spent more were turned away.

Today, the 56-year-old restaurateur can count on $168 a head for his four-course menu on Saturday nights, or $178 -- $278 paired with wines -- for a larger, seven-course tasting menu. "It allowed us to stay in business," Mr. O'Connell says. Most of all, he relishes the fact that his guests must put themselves "in the kitchen's hands." The prix-fixe menu, which Mr. O'Connell likens to an admission ticket, allows him to show guests that he knows what's best when it comes to dinner fare.

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How the Menus Stack Up

We assembled a team of experts to rate prix-fixe and tasting menus on the variety of dishes and overall value for the money. Some menus change depending on what's in season; we used those in circulation at press time. Our panel included Dorothy Cann Hamilton, founder and chief executive officer of the French Culinary Institute in New York; Sheryl Kimes, associate dean of the Cornell University School of Hotel Administration; Michael Lomonaco, executive chef and managing partner of Porter House New York; Tim Ryan, president of the Culinary Institute of America in Hyde Park, N.Y.; and Clark Wolf, food and hospitality consultant.
-- Jamin Warren

Davidburke & Donatella

New York

PRICES $85, five-course tasting menu
SAMPLE ITEMS: Kumamoto oysters with pineapple-vanilla mignonette; braised oxtail with cauliflower puree, butternut squash and roasted fingerling potato
COMMENT: Fancy-sounding dishes that are actually simple can be red flags on a fixed-price menu. Here, "heirloom tomato carpaccio" is another way of saying they're sliced finely, said consultant Clark Wolf. Others praised the freshness of items, including the oysters, which have to be brought in weekly.
VERDICT: The price is reasonable for New York City, but ask your waiter for complete descriptions of the food before committing.

Inn at Little Washington
Washington, Va.
PRICES: $178, seven-course tasting menu/$278 with wine pairing

SAMPLE ITEMS: American osetra caviar with a crab and cucumber rillette; minced squab with Virginia peanuts and shiitake mushrooms

COMMENT: The most expensive in our test, this menu had some experts wondering if it was overpriced, considering ingredients like American caviar, which is cheaper than the imported stuff. The Inn says most imported caviar is embargoed, and what is available is prohibitively expensive. Other pricey delicacies like foie gras and lobster left Chef Lomonaco impressed: "If I ve come into this restaurant, I'm there for a reason."
VERDICT: Perfect for impressing potential clients or future fathers-in-law

Alinea
Chicago
PRICES: $125, 13-course tasting menu
SAMPLE ITEMS: Squab with strawberry, oxalis and long peppercorn; mackerel with tumeric, bee balm and poppyseed
COMMENT: Our panel agreed that the menu here had a few too many courses and could overwhelm the palate. Alinea says many customers like the variety that so many courses offer. CIA President Tim Ryan liked the word economy of the descriptions, which he says helps diners quickly see whether they want to order the set menu.
VERDICT: Exhaustive selection can cause diner fatigue, but unique pairings show chef's creativity.