Don’t mess with the chef!

Don’t get chef Catherine de Zagon started on Caesar salad. When a customer recently walked into her Brooklyn Italian restaurant Locanda Vini e Olii requesting the dish, he was met with a flat refusal.

“Don’t have it, don’t know what it is, will never have it,” says de Zagon of the dish, which is commonly thought to have been created by restaurateur Caesar Cardini at his Tijuana restaurant in 1924.

“Not that I think there’s anything wrong with it, but it’s Mexican, not Italian.”

Only in New York do diners wait months for a table at the latest hot spot, only to insist on ordering a dish that’s not among the restaurant’s specialties — or even on the menu, for that matter.

Whether it’s average folks complaining that the market fish smells like the ocean, or celebs like Woody Harrelson and Russell Simmons requesting vegetarian dishes at trendy steakhouse STK, there’s one thing that’s on the menu at many of the city’s best eateries: extreme pickiness.

“A lot of [people] think they’re experts, which they’re not,” says Le Pescadeux owner Chuck Perley of diners. He thinks the rising popularity of cable TV cooking shows is responsible for the escalation of demands from finicky New York City foodies. “There’s a night-and-day difference between now and when I opened in 1981.”

And chefs are increasingly refusing to indulge requests, even if it means losing customers.

“We’ll ask you upfront, ‘Do you have any food allergies, things that you absolutely can’t eat or really don’t want to eat?’ ” says chef-author Anthony Bourdain.

“From that point on, though, [chefs] get a little testy if you’re asking them to ruin what they see as their best efforts.”

Momofuku’s David Chang doesn’t care that you like your noodles with broccoli. The Breslin’s April Bloomfield isn’t going to burn your steak until it could be used to pound nails through the hood of a Buick. And no, de Zagon isn’t going to drown your spaghetti in Parmesan cheese.

“When people ask for [Parmesan], we politely tell them we don’t recommend it and that they try [the dish without it] first,” says de Zagon.

At her Tuscan restaurant housed in an old apothecary shop in Clinton Hill, Brooklyn, de Zagon — who was raised in Florence, Italy — prides herself on serving completely authentic cuisine.

“Sometimes we’re asked to put [Parmesan] on fish soup, and we’re a lot firmer there. We’ll tell them it’s not recommended, then walk away and pretend we didn’t hear them,” she says, only half-jokingly. “Or we’ll give them a dirty look.”

Requests for veggie-friendly items also tend to miff chefs — especially at meat-centric restaurants.

“I don’t know if it’s true,” says Bourdain. “But there’s a story that when customers started annoying [David Chang] by complaining about the lack of vegetarian options at [Momofuku] Noodle Bar, he changed the menu and put, like, pork in every dish.” (When asked for comment, Momofoku did not deny this claim.)

On the menu at Chang’s popular sister restaurant Momofuku Ssam Bar, there are sections dedicated to “Country Hams,” “Offal” and “Fish & Shellfish.” There are also notes that read “Please let us know if you have any food allergies,” “No substitutions or special requests” and “We do not serve vegetarian-friendly items.”

Well, Momofuku too, pal!

Celebrated chef April Bloomfield of the Spotted Pig and the Breslin also has a mercurial reputation in the industry — and online.

Earlier this year, in a posting titled “Menu Snobs,” a menupages.com user named “Erin” complained that the Breslin’s kitchen wouldn’t cook her pregnant friend’s steak medium-well, refused to serve her a salad with dressing on the side and declined her request for well-done scrambled eggs.

“They refused, saying they only cook them one way. I mean, how hard is it to keep it in the pan one minute longer?” Erin cyber-whined. “Wet eggs are gross to me, I wanted them well done. Not an odd request. Nope, refused.”

While Bloomfield declined to comment, she’s far from the only chef who discourages crossing the cook. In his 2001 tell-all “Kitchen Confidential,” Bourdain revealed that customers insisting on well-done steaks often get the worst piece of meat in the house.

At Locanda Vini e Olii, de Zagon serves very lean Piedmontese beef that “has to be rare” so it doesn’t dry out — still, she says she’s willing to cook it medium for pregnant customers.

But while her Brooklyn regulars usually eat from the menu, she says Manhattan diners tend to see restaurants as their own personal pantries.

“When you have to eat every one of your meals outside [your house], you want things your way,” says de Zagon, who used to manage Manhattan’s Balthazar while her husband and partner at Locanda was a manager at Cipriani.

Dining divas, it seems, come with the territory.

“I’ve had guests go through the trouble of sending their steak back to the kitchen so we can slice it for them. They have a steak knife. I don’t understand,” says chef Franklin Becker of trendy Meatpacking District steakhouse Abe & Arthur’s. “I think there’s a certain type of customer that’s going to be needy,” he adds.

Chef Todd Miller of Meatpacking District steakhouse STK puts it more bluntly: “There are some people who are just difficult and shouldn’t be eating in public.”

Not long ago, Le Pescadeux’s Perley recalls, his SoHo restaurant served turtle. No, they weren’t cooking turtle. Perley says a man brought his pet turtle — one of his few possessions left after a divorce — into the restaurant and asked the kitchen to prepare a raw hamburger patty for his shelled dining companion, “Sammy,” and a seafood entree for himself. The kitchen obliged.

In the end, it isn’t always about the request as much as how or why the request is made.

“I think the line is when you’re abusive or indignant or demanding or working out some personal business on your service staff,” says Bourdain.

“If you come in half-drunk and start demanding stuff off the menu like they do in Hollywood, that’s not gonna fly. I think the way you ask has a lot to do with it — the timing and tenor and tone of your request.”