The Big Bucks Burger at the Downstairs Bar pairs a Kobe beef burger with a bottle of Champagne. Photo by Clint Karlsen. The Big Bucks Burger at the Downstairs Bar comes with or without Champagne. Photo by Clint Karlsen. Meat quality and toppings set gourmet burgers apart from standard ones, local chefs say. This burger features Kobe beef. Photo by Clint Karlsen.

The humble hamburger -- a quintessential part of casual American cuisine and a staple of backyards, bars and ballgames -- has landed on the most unlikely of places: the menus of gourmet restaurants everywhere.

And while it's a casual food, people are paying some pretty formal prices -- $10 and more -- for the gourmet version.

But these aren't fancy prices for the hamburgers of school cafeterias or the Golden Arches; they're hip hamburgers that transcend burger classification and are actually closer to haute cuisine than hot-off-the-grill chuck patties, local chefs say.

The word "gourmet" should not be intimidating when it comes to hamburgers because it's code for the best meat and toppings, said Hubert Keller, chef and owner of Burger Bar in Mandalay Place, 3930 Las Vegas Blvd. South.

Keller is the creator of possibly the most expensive burger in Las Vegas, the $60 Rossini burger. It's made with American Kobe beef, a version of the Japanese Kobe beef, the most expensive and flavorful in the world, he said. But that's not all. The Rossini is topped with seared fois gras and shaved truffles nestled on a fresh onion bun. Madeira sauce is served on the side. No iceberg lettuce for this burger.

It's popular with customers despite the price tag, Keller said, because "burgers are in, I think. They're very popular. It is definitely comfort food, it is something very American. For some people, saying they ate a burger was something to be ashamed of. Now, (with gourmet burgers) they're proud. ... It has suddenly become a meal."

This gourmet burger trend started in 2001 in -- where else? -- New York City, when four-star chef Daniel Boulud introduced a hamburger in his DB Bistro Moderne.

Everyone thought that was cool, said Keller, who also owns Fleur de Lys in Mandalay Bay, 3950 Las Vegas Blvd. South.

Ultimately, the gourmet-ification of burgers is just a way to present something comforting and familiar in a new and exciting way, local chefs said.

You don't have to pay $60 to enjoy the experience. Keller offers a $15 Kobe beef burger, or a $25 surf-n-turf burger, a Kobe patty topped with Maine lobster.

There are all kinds of incarnations at Burger Bar made with unique toppings, such as asparagus.

The Kobe beef burger, at $12.95, is the second-most popular item on the menu at the Downstairs Bar, 11261 S. Eastern Ave., said owner Brett Rosselli. Made with 8 ounces of American Kobe ground beef, it's topped with applewood smoked bacon, avocado slices, Romaine lettuce, tomatoes, American and Swiss cheese.

Kick it up a notch by ordering the Big Bucks burger, which is the same Kobe beef burger paired with a bottle of Dom Perignon. It sells for $150.

"I put it on the menu as a novelty," Brett said. "But everyone's hot about Kobe beef burgers. Not only is it phenomenal beef, it's become a buzzword for quality. People know what Kobe is, and they're willing to pay $12, $20 and more for a burger."

Barry Dakake, chef at N9NE steakhouse in the Palms, 4321 W. Flamingo Road, put the whole price thing in perspective for those who want to try a gourmet burger but are afraid of getting ripped off. He offers a Kobe burger with homemade ketchup, aged cheddar cheese, balsamic onions and applewood smoked bacon, for $25.

"If you're going to spend that much on burger, it better be the best damn burger you ever ate," he said. "You get what you pay for with a Kobe burger, which are good ingredients. The burger is juicy, succulent. It's a great entree."