It's a balmy March evening just before the official arrival of spring, and a few diners are already happily venturing to the small tables outside Red Rooster, chef Marcus Samuelsson's eatery on Lenox Avenue in the heart of Harlem.

But outside isn't really the place to be.

No, to feel the buzz that is Red Rooster, one should really be perched on a stool at the horseshoe-shaped bar inside. It's elegant, made of different hues of wood, but more importantly, it's occupied by different hues _ and ages, and types _ of people. On this evening, the guests are black and white, Asian, old and young, gay and straight.

They may be sipping one of Red Rooster's signature cocktails _ the Earl of Harlem, for example, bourbon with Earl Grey tea and coriander syrup. They may be snacking on the addictive cornbread with honey butter while they wait for a table. Or, like Naveen Pesala, a physician who's worked nearby for five years, they may be reconnecting with an old friend for a quick glass of prosecco.

But they're all participating in something pretty rare in New York: a truly diverse, high-end dining experience, and one that brings people to Harlem from everywhere in the city.

"I've even run into patients here," says Pesala, who's joined by a friend from SoHo for the evening. "It's a very unique place."

Unique is certainly the word to describe Red Rooster, some 15 months after Samuelsson launched it. There was plenty of hype then, and no wonder: Even among celebrity chefs he was a celebrity, known for his speedy rise in the restaurant world (executive chef at the renowned Aquavit at age 24, and the youngest chef to earn three stars from the New York Times); his telegenic TV persona; his hip personal style; his unusual background (born in Ethiopia, raised in Sweden); and of course his admirers in high places. He was chosen to be the chef at President Barack Obama's first state dinner, and Red Rooster hosted a recent Obama fundraiser.

With so much attention, there was bound to be some quibbling. Some purists say the food, a mix as eclectic as Samuelsson himself, isn't really soul food and should be. Others grumble about the prices (high for the area perhaps, but not for high-end restaurants elsewhere). A blurb in the Zagat guide calls the place "groundbreaking" and "uber-popular," but also notes that "'Unless your name is Obama,' it may be tough getting a table."

More striking, though, is what people _ even those who don't feel they can pay $15 for a cocktail _ feel it is doing for Harlem.

"It's a great thing for the neighborhood, because he's such a big name," says Gloria Dawson, a graduate student at Columbia University who blogs about Harlem restaurants. "And the best thing is that this will encourage other people to take risks, and open other places in Harlem."

Dawson says she's a particular fan of the fried yard bird (that's chicken) and the shrimp-and-grits dish. She's also partial to that Earl of Harlem cocktail. But mostly, she says, she loves the scene.

"It's visually stunning, with all the artifacts and knickknacks and Harlem art," she says. "It's also incredibly lively." And most strikingly, she says, "You really never see this much diversity in other restaurants."

That's a feeling echoed by food writer Andrew Knowlton, restaurant editor at Bon Appetit magazine.

"I grew up in the South, and there was just a lot of diversity in the dining rooms _ especially after church," says Knowlton. "Now I live in New York, and of course it's a super-diverse city, but when it comes to dining out, well, it's pretty sad that way. So Red Rooster has really done a wonderful thing."

Knowlton feels the restaurant is a reflection of Samuelsson himself _ and why not? "With his crazy background, Marcus has been grappling with who he is and where he fits in," he says. "So he decides to move to Harlem and open this restaurant. He knows the power that restaurants have over a neighborhood."

But can a restaurant be both an international destination for high cuisine and a comfy neighborhood joint? That's a dynamic the 41-year-old Samuelsson has clearly considered very carefully along the way.

His first step was to move to Harlem, something he did about eight years ago. He'd lived in various neighborhoods, but had always been drawn uptown. He wondered why many other New Yorkers hadn't been. "Why does someone from 89th and Columbus go to Paris more often than Harlem?" he asks, speaking to a reporter one afternoon during the lull between lunch and dinner. "That's a real challenge."

But it quickly becomes clear that Samuelsson's journey to Red Rooster began well before that, when he was a young black man in Europe, adopted from Ethiopia with his sister. He had a crazy plan of being a top chef.

"Being a person of color, things were very clear," Samuelsson says. "Being a chef at that level I wanted just wasn't an option."

"So you have two possibilities _ you quit, or you smile and do it better," Samuelsson continues. "I chose the second. And I said, `I have to go to America.'"

After his success at Aquavit, Samuelsson opened several restaurants, not all roaring successes. But Red Rooster is clearly his most ambitious project yet.

"It's so hard to say that something is one-of-a-kind," says Dana Cowin, editor-in-chief of Food & Wine magazine. "But Red Rooster truly is. It's the food, it's the vibe. But it's also a cultural meeting place _ for people in the arts, for people downtown, for people of New York, for people of the world. It's almost more like a 1920s cafe in Paris, in that respect."

Lenox Avenue may not be the Boulevard Saint-Germain, but it was, for Samuelsson, an irresistible draw, given its rich historical associations with figures like Langston Hughes and James Baldwin. But it isn't just history that determined his restaurant's location. There's a big subway stop at Lenox and 125th, a few steps from the restaurant. The bus goes right by. The express train from Times Square takes about 10 minutes.

Once he found his spot, Samuelsson filled it with tiny and telling touches _ reflecting both his own journey, like an ABBA album, and the neighborhood he calls home. Colorful art from Harlem fills the walls.

He takes us downstairs, where workers are finishing construction on Ginny's Supper Club (the room has just opened for business). The sleekly designed space will host different kinds of music _ jazz and Latin, for example. Only this one, Samuelsson notes, "will have really good food." Music is a theme at Red Rooster upstairs, too: The Sunday gospel brunch is extremely popular, and there's a nook in front where a DJ comes to spin.

Even the bathrooms are sort of a display case _ filled with fraying black-and-white photos of Harlem in years past. "So if you have a boring date, you don't need to come out of here at all," he quips, showing off the walls.

But even a boring date, while unfortunate, wouldn't keep most people from the dining room, which Samuelsson often walks through, shaking hands. A middle-aged white couple stops him: They want to report on a recent trip to Ethiopia. A while later, a 91-year-old black woman comes in for coffee. Samuelsson admonishes an assistant more than once to go check on her. "People need to understand why she left her house," he says. "It's not for the coffee."

Damaa Bell is a schoolteacher in the area, and also writes a blog on Harlem culture, Uptown Flavor. She herself doesn't go to the restaurant that often, but would definitely consider it as a spot to bring visitors to the city.

She notes, though, that the prices might keep some Harlemites away. Indeed, the cost of a meal at Red Rooster varies a great deal. A steak frites dish costs $31, and there's a Sonoma County wine for $450. But there are bottles in the $30 range, a happy hour with cheaper drinks, and a lunch special for $20.12 with a menu typically reflective of Samuelsson's background: a spicy peanut soup, his Helga's Meatballs (inspired by his grandmother), and a devil's food cupcake.

Technology executive Vikas Sood is eating just that lunch one day at the bar, part of an ambitious sweep of the city's culinary hot spots before he starts a new job.

The verdict of this foodie? "It's really good," he says. "It may not be typical soul food, but it's good!"

After dessert, Sood is heading to sample the new Lenox Coffee nearby. Red Rooster, some point out, is not the only culinary example of a revitalized Harlem.

"It's a much bigger story," says Tim Zagat, founder of the famous guide. "It's been happening for the last decade. But Marcus has been front and center on the public side of this story, because of who he is, and he's doing a great service to Harlem _ and to us all."

Speaking to Samuelsson, though, one senses he'd consider it a shame if Red Rooster were the end of the story, rather than a beginning.

"What I want is to create normalcy here," he says. "I resent it when people come to Harlem to take pictures and get back on the tour bus. This is an opportunity to get off that tour bus."

After all, he asks: "Why should New York City be confined to 50 blocks?"