It is noon at the Booeymonger delicatessen in Ballston and three employees, wearing uniformly forest-green polo shirts, white aprons and baseball caps, punch orders into the cash registers. Four more work the sandwich line behind a waist-high counter, juggling turkey slices and mango chutney to construct the "Sheherazade," or muenster cheese and alfalfa sprouts for the "Pita Pan."

With its bright yellow walls, high ceilings and big windows, the month-old Ballston restaurant looks little like the original Booeymonger in Georgetown. It is not as busy either, bustling usually only at lunch.

But the Ballston store has a big advantage: It is a part of one of the latest trend in restaurants -- in industry jargon, "fast-casual" chains, with more sophisticated and pricey takes on the old ham sandwich. These include national chains like Cosi and Corner Bakery. They have grown by attracting professionals too time-crunched for table service but who don't mind dropping as much as $9 on lunch. Booeymonger targets people willing to pay a little more for options like spinach mushroom salad and hummus. Sandwiches cost $5 to $6.

The patrons here today are mostly prosperous professionals from the technology firms and nonprofit associations in the Arlington neighborhood. There is Betty Bryant, 46, director of a children's scholarship fund, who is sitting by herself. She has had lunch at the Ballston Booeymonger almost every day since it opened. She likes the restaurant at the local Holiday Inn just as much, but Booeymonger is a few blocks closer to her office. "The Holiday Inn is cheaper," she says between bites of her chili dog, "but I come here because I'm lazy."

Rick Broderick, 49, an executive at a nearby hotel-management company, has never heard of Booeymonger but tried it based on the raves of a co-worker. "It's nice just to have another place," says Broderick, who often eats at the nearby Hilton Hotel and Potbelly Sandwich Works, another upscale fast-food restaurant. Broderick says he likes his Italian submarine, but the consultant sitting across the table from him for this business lunch, Elliott Woltz, complains that his roast beef is a little overcooked.

Fast-food chains selling gourmet sandwiches and desserts in well-decorated restaurants have been around since the 1980s. Au Bon Pain, serving seafood bisque and chocolate croissants, and Fuddruckers, with its beef, ostrich and salmon burgers, pioneered the concept. The business surged in the late 1990s when chains such as Chipotle, a Mexican cuisine chain owned by McDonald's Corp., and Panera Bread, a bakery and sandwich shop, began rapidly expanding.

The chains are growing about 12 percent a year compared with 5 percent for traditional fast-food restaurants. But fast-casual chains still account for only about 6 percent of all restaurants while fast-food restaurants are three-quarters of the $275 billion industry.

The original Booeymonger, which opened in 1973, was a pioneer. The cramped and cozy restaurant was a late-night hangout for students at Georgetown University, on a corner surrounded by townhouses only a few blocks from the bustle of M Street. Only the food is the same: classic deli fare like hot pastrami sandwiches, bagels with lox and strawberry swirl cheesecake. One early success, a turkey sandwich with Russian dressing dubbed the "Patty Hearst," is still on the menu. The unpretentious food draws a diverse clientele. Regulars at the Georgetown restaurant, according to the owners, include John Kerry's security detail, Patrick Ewing and a local Alcoholics Anonymous group.

Since then, two more Booeymongers have appeared, in Chevy Chase and Bethesda, in older residential neighborhoods near stores and other restaurants. For the latest, the three owners -- Leslie Samuel, Ron Vogel and Rick Gossett -- looked at spaces in Rockville and Tysons Corner but balked at the high rents. "Our food costs are higher than your average pizza place, so we can't spend as much on rent," said Vogel, a New Yorker who attended American University.

Vogel, 54, and Samuel, 58, are lunching at their new restaurant and talking about how the place got its name. Another partner, now departed, adopted it from a student newspaper he started in Ohio. Vogel, who visits all four restaurants twice a day, seems a little stressed; Samuel works out of the Georgetown restaurant and is more laid-back.

While it is a reasonably priced location, Ballston is a little bit of a risk, too. The neighborhood emerged as a destination for the young and affluent only in the last five years and doesn't have much nightlife, a departure from the chain's other locations. The owners are betting the Ballston store, which is next door to Marymount University and its 3,900 students, will also evolve into a college hangout.

Since there aren't many restaurants in this section of Ballston, the Booeymonger may also get a second chance to convert customers like Woltz, the customer with the overcooked roast beef.

Connie Polanec, 35, an executive at a hotel and resorts company, says Booeymonger was one of only two restaurants within a few blocks of her office. "We were kind of anxious to see what was coming in," she says as she picks up a takeout order.

Marc Einhorn, a commercial property manager for the Jaffe Group, a Chevy Chase real estate company, says he thinks Booeymonger will succeed in Ballston, at least a quarter of whose residents range in age from 25 to 34. "There's a lot of foot traffic, a lot of high-rise condominiums there," he says. "It's a popular place for people in their twenties and early thirties and that's the kind of demographic that Booeymonger is going for."

The Ballston restaurant hums from 11 a.m. to 1 p.m., when it does three-quarters of its business for the day. After 2 o'clock, orders slow to a crawl and the few stragglers who come in eat alone. A couple of employees takes their lunch breaks and find a seat. The kitchen empties as the 12 people on the day shift get ready to leave. Only four people work the night shift, which starts at 3 p.m. and lasts until the restaurant's 10 p.m. closing.

Samuel, one of the owners, leans back in his chair and surveys the restaurant as the lunch crowd thins out. "One guy opens up across the street and half your business is gone," he frets. But for now at least, he can relax.

Delmar Obaji, a frequent customer since Booeymonger opened in Ballston, gets his sandwich from co-owner Ron Vogel. Entrees include the Tuna Turner and Patty Hearst.Booeymonger co-owners Leslie Samuel, left, Ron Vogel and Rick Gossett sit outside the Ballston location and review their new menu. Standing behind them, from left, are employees Ravi Abeynayake, Ajith Wellage, Mohammad Ishagne and Geoffrey Vogel.