The hamburger ain't broke, but it is being fixed in all sorts of imaginative ways lately as the burger category on restaurant menus expands. Popping up alongside the traditional hamburger are all kinds of specialty burgers with distinctive names.

Some have spicy flavorings or zesty marinades. Others are served on special bread or garnished with unconventional toppings like grilled pineapple or crisp tortilla strips. A few burgers are served with spicy dipping sauces, and others are just much smaller or much bigger than average.

“People definitely like the familiar with a twist,” says Michele Schmal, vice president of foodservice for The NPD Group, a market research provider.

“New flavors and toppings are a great way to make a menu staple like hamburgers fresh and exciting,” she says.

From quick-service chains such as Hardee's to high-end establishments like Wolfgang Puck, restaurants are re-inventing the burger to further capitalize on consumers' devotion to America's favorite sandwich.

According to The NPD Group, experimentation with new burger flavors may be paying off for casual dining restaurants, and it may be driving increases in traffic. In 2005, American consumers made 87 million more visits to casual dining restaurants and ate nearly 47 million more burgers at those establishments than they did the previous year.

This is part and parcel of the resurgence of beef that's been underway the last several years, says Mark Thomas, vice president of global marketing for the National Cattlemen's Beef Association (NCBA).

The idea that burgers can be more gourmet is catching on, he says, and it's one way restaurants are trying to differentiate themselves from the competition.

“Part of the reason we see this love affair with the great American hamburger is that it's an icon of American cuisine,” Thomas says. People just have a passion for the great flavor of hamburgers, he says.

Ellen Gibson, NCBA's executive director of checkoff-funded new product initiatives, agrees.

“Hamburgers are loved by just about everybody,” she says. People know the hamburger is a good, safe choice, and they are willing to experiment a little with different flavorings or toppings.

Eight out of 10 commercial and noncommercial foodservice operators serve hamburgers, Gibson says, and each establishment wants to offer a signature burger to distinguish itself and draw more business.

One example at the fast-food level is Hardee's, which has expanded its Thickburger line and pared down the rest of its menu as a way to set itself apart from larger competitors. In the past year, the burger chain has reintroduced its Chili Cheese Thickburger and has launched the Jalapeño Thickburger, the Philly Cheesesteak Thickburger and the Spicy BBQ Thickburger.

“From a marketing standpoint, we don't have the same budget some of our competitors do, so we don't really market multiple products to multiple demographics,” says Jeff Mochal, public relations manager for Hardee's.

“Hardee's is all about premium burgers now,” he says. “That's really the focus of our menu, and we're trying to reach out to a core group of people who we call ‘young, hungry guys.’”

Extensions on the Thickburger product line will continue, Mochal says, as a way to feed America's love for good, high-quality burgers.