In a city of seemingly infinite dining options, where menus gallop on for pages and a single appetizer can contain an entire shopping list of ingredients, these places offer little or no choice at all.  What they sell is usually made well, often in several different ways, with top-notch components and at least a side dish or two. But the bill of fare is decidedly limited, if not downright obsessive. Take it or leave it.  Many New Yorkers are taking it.  One two-block stretch of Spring Street has a creperie, a café dedicated to chocolate cake — a Portuguese transplant called the Best Chocolate Cake in the World — and even a business, Rice to Riches, that has managed to thrive since 2003 on rice pudding alone.  “Everybody has some kind of rice in their culture or their background,” said Anna Gallo, its operations manager. “And everybody has that kind of very warm, passionate relationship with rice pudding — maybe it was something their grandmother made, or something their mother made or something original to their country. So that’s why people keep coming.”  Granted, New York has long had a soft spot for the niche restaurant; arguments over the best pizzeria, dumpling counter or hot-dog stand are part of the collective parlor game. But as fast-food chains — wildly successful traffickers of the single-item concept — compete with one another by offering ever more variety, this new wave is using pedigreed chefs and high-quality ingredients from specialty purveyors to turn out so-called slow food fast.  “You used to bring your date to McDonald’s or the drive-in — that was like the cool place where young people went, and at some point in time fast food lost its cool,” said Daniel Holzman, who has worked in elite kitchens like the one at Le Bernardin and is now co-owner and executive chef of the Meatball Shop. “For us it became this opportunity ” he added, to “create a fast-food restaurant for our generation that has all the values, all the quality that we expect.”  This comes as the appetite for affordable comfort food shows no signs of abating; witness the flood of burger joints around the city.  Mr. Holzman said customers at the East Village restaurant where his business partner, Michael Chernow, tended bar were constantly asking for recommendations not for the best restaurant but for the best single items, like pizza, burgers or tacos. “That’s what people are excited to find,” Mr. Holzman said, “especially because that’s what everybody’s obsessed with — you can blog about it.”  Food television and blogs have stoked the obsession, offering lists, reviews and shows that anoint the “best of,” which in turn encourage lively comment threads and send diners out to taste for themselves. MenuPages.com even has a Find-a-Food search function, inspired by the craving of its founder, Greg Barton, for white clam sauce.  Sarita Ekya, who opened S’Mac with her husband, Caesar, in 2006, said they had been inspired after eating at the niche restaurants downtown, and settled on mac and cheese while dining at Peanut Butter and Company, which is devoted to the spread.  “We noticed that there was a really strong following for mac and cheese on the Internet,” she said, with “people going out of their way” to find their favorite versions.  Although single-food restaurants have sprouted across the country, they tend to be most successful in major cities, where the population is dense and broad enough to guarantee a crowd for the star product, said John D. R. Walker, a professor at the school of hotel and restaurant management at the University of South Florida in Sarasota.  “When you get the population spread out, I mean, am I going to get in my car and drive to a place to get meatballs when there are so many places between us and the meatballs?” Professor Walker said. “It’s got to be spectacular.”  Not every comfort food is ready for its close-up: New York shops committed to grilled cheese sandwiches, Philly cheese steaks and popovers have failed in recent years. “Certain movie stars can carry a movie; certain foods can carry a restaurant,” said Marc Glosserman, the founder of Hill Country Chicken.  To make a whole menu, the main attraction must set off some sort of nostalgic response in the diner, restaurant owners say — whether memories of lobster rolls in Maine or that steaming bowl of mussels enjoyed on vacation in Europe.  “Fried chicken is comforting because it has an emotional touch point, but it’s also cravable,” said Elizabeth Karmel, chef at Hill Country. “We had no idea just how desperate people would be to eat fried chicken.”  The spotlighted food must also transport other flavors, so regulars do not feel that they are eating the same old thing — even though they are. That is part of what attracted Dana Nicholson, 48, to Flex Mussels when it first opened uptown, though he now frequents the outpost in the West Village, closer to his SoHo home.  Extolling the virtues of mussels from Prince Edward Island — the restaurants import their specialty directly — he said he found them cleaner-tasting and meatier than other varieties.  “They’re great just steamed with nothing, but also with all the ingredients,” he said. “These you can just keep eating.”  A version of this article appears in print on November 29, 2010, on Page A20 of the New York edition with the headline: The Menu: One Entree. That’s It. Order Reprints| Today's Paper|Subscribe
Restaurants with menus designed around one food or one ingredient have caught on with New Yorkers eager to find the best of something, or satisfy nostalgic cravings.