Salmon is the new cheesesteak. But some in Philly still don't know it.

Cut South Philly from the map of Philadelphia. While you’re at it, carve out the center of the city entirely.

What remains, when you’re through, will be the territory of the salmon cheesesteak.

The sandwich is a paradox — so popular it inspires pilgrimage and half-hour waits on the sidewalk, yet largely unchronicled by food media and unknown to half its home city. In North and West and Southwest Philadelphia, in the western suburbs and the urban centers of South Jersey, the salmon cheesesteak thrives.

When "The Tonight Show’s" Jimmy Fallon rolled into Northeast Philly with the Roots’ Tariq Trotter for a televised home-cooked meal, a salmon cheesesteak is what he was served. It’s been repped as a favorite by hip-hop stars Meek Mill and Wale.

The sandwich has traveled mostly by word of mouth and social media. It presides at more than 30 restaurants in a bullseye ring around Philadelphia’s middle. Most are small Black- or Muslim-owned takeouts serving their neighborhoods.

At tiny, red-awninged Harvinskins Seafood in Camden, New Jersey, the seafood cheesesteak has blown up into viral popularity.

More than half of Harvinskins’ business is now cheesesteaks made with salmon, said co-owner Latasha Gaylord, who runs the business with brother Robert Muse. Harvinskins’ hungry fans drive in from New York City and D.C. A New York motorcycle club made the little takeout into the endpoint of its weekend rides.

“They’d come down like every two to three weeks,” Gaylord said. “A whole bunch of ‘em would come down just to eat.”

Harvinskins’ rendition comes with a half-pound of flaky Norwegian fish on a roll from 70-year-old Deluxe Italian Bakery. The fish is generously buttered, seasoned with more Cajun flavor than a first-line brass band in Treme, grill-chopped on a flat-top and melted down with American cheese that disappears glisteningly into the meat. Order the seafood version, and it comes crowned with six stately, meaty prawns.

The attention is recent. But the salmon cheesesteak's roots go back more than a decade in Philadelphia.

“It's been around. You just have to be in the urban community to know about it,” said popular Cambodian American food vlogger Jeff Lek.

On his JL Jupiter YouTube channel since 2019, Lek has been the salmon cheesesteak’s most prominent evangelist, broadcasting the sandwich far beyond the neighborhoods where it's served. “It’s something that we've enjoyed within the hood for a while,” he said.

Philly-grown chefs have successfully brought the creation to Delaware and D.C. and Maryland, and to cities as far-flung as Atlanta and Kansas City.

The fundamentals are simple. A hoagie roll forgiving enough hold up to cheese and fish. Seared and grill-chopped salmon filet. Cheese that melts imperceptibly into the meat. And often, vegetable additions such as broccoli or spinach.

But there are few rules for a young food. The seafood-dense version at A King’s Cafe is loaded with crab and shrimp and red bell peppers. West Philly’s Korean-owned Lee’s Deli makes a veggie-rich version with optional sweet chili sauce that amounts to stir-fry in a hoagie.

At North Philly’s Ummi Dee’s, chef Hannah Ahzai marinates and seasons fresh salmon belly, spurning American slices for a rich multi-cheese Mornay she developed with the help of fellow chef Kurt Evans.

Perhaps the wildest take comes from Zoagies — a deep-fried hoagie truck from South Jersey native Ezell Barnes now stationed on the side of a busy freeway in Bear, Delaware, just southwest of Wilmington.

Barnes is a dedicated showman whose menu and sales patter is inflected with a Z-fronted language he calls "Zinglish." His two-truck "Zoagieland” is an alternate hoagie universe, with stacked-up seafood hoagies whose fat-crisped rolls recall the fluffy crackle of Texas toast.

But Barnes' customers kept asking for salmon cheesesteaks, which he added this year. His version is a contrast of crisp bread and generous salmon, bold-seasoned shrimp and a grace note of charred broccoli.

“The people wanted it and so I added it," Barnes said. "And when I did, I said, ‘Oh my Zod, zis is zucculent zalmon.”

A brief and contested history of the salmon cheesesteak

According to one account, the history of the salmon cheesesteak began a little more than a decade ago, with a North Philly barber named Marvin.

The way Albert Alwyn tells it at his North Philly takeout spot, Bella’s Restaurant and Grill, Marv used to be a barber at a little shop down the way called Freddie’s. And Marv didn’t eat red meat.

So Marv asked Bella’s chef, Alwyn’s late sister Tracy, to make a cheesesteak he could eat.

“She was for the community,” Alwyn said, “If you wanted something special, she would make it for you.” His sister concocted a salmon cheesesteak with some broccoli on the shop’s well-seasoned flat-top. Bella’s already served a salmon and rice bowl, so the ingredients were on-hand.

The rest. Alwyn said, is history.

“It just took off,” Alwyn said. “All of a sudden everybody was serving them. But ours must have been special.”

The shop had to adjust its hours to accommodate salmon mania, pushing later into the evening. Its Instagram account shows visits from hip-hop legends Doug E. Fresh and Charlie Mack — not to mention check-ins by rapper Meek Mill.

“He used to come down here with his girlfriend,” Alwyn said. He called over to Bella's cashier. “Hey, what’s Meek Mill’s old girlfriend? The rapping one?”

“Nicki Minaj!” she shouted back.

“Yeah, Nicki Minaj,” Alwyn said. “Meek would come in. She mostly waited outside.”

Until very recently, documentation of salmon cheesesteaks has been scant. But in 2015, a Philadelphia Inquirer reporter stopped into Bella's to ask how a new Housing Authority office had affected lunch business — and was told by line cook Demetrius Goudelock that Bella's had "started" the salmon cheesesteak.

Alwyn can’t remember exactly when they began serving it, but searches of Facebook and Twitter show 2010 as the year the salmon cheesesteak broke big. For two years, nearly all mentions of salmon cheesesteak referenced Bella’s.

Before that, the history is murkier. Bella’s may have launched the salmon cheesesteak — but it’s unclear they were the first to serve it.

The earliest records of salmon cheesesteaks on Facebook and Twitter came in late 2009, referencing a defunct North Philly takeout called the Cheesesteak Factory. Ummi Dee’s owner Ahzai says she’s pretty sure she had it in Southwest Philadelphia even before that, at long-gone Samiches Deli.

YouTube food chronicler Lek said he’s gotten heated correspondence from restaurants claiming and counterclaiming to be the cheesesteak’s inventor.

“People get really sensitive about who’s the originator,” said Lek, who suspects it's existed far longer than the public record shows. “Whoever first got the idea to put it in their restaurant, there's a good chance that it's been kicking around at cookouts and elsewhere for longer. Meaning whoever claims it can’t even claim it.”

When is a cheesesteak not a cheesesteak?

But the salmon cheesesteak is also divisive. Philadelphians have long made a pastime out of debating the exact composition of a proper cheesesteak, not to mention how some guy in upstate New York is screwing it up.

When Fallon ate his salmon in 2018, local media responded with confusion. A similar reaction followed a stray tweet about salmon cheesesteaks by rapper Wale in early 2019.

“I live in Philadelphia,” clapped back local journalist Jason Peters. “If anyone ordered a salmon cheesesteak, they are getting roasted immediately. No hesitation.”

A reporter at the local FOX outlet posted a poll on Twitter, asking whether “authentic Philadelphians don’t tolerate this salmon and chicken stuff.” About 80% of FOX fans attested that beef was the only steak.

A decade in, salmon cheesesteaks remain all but unfindable in the city’s center. Italians, and the Italian American food culture that birthed the cheesesteak, have long resisted mixing seafood and cheese. Food historian Ken Albala has linked this taboo less to incompatible flavors than ancient pre-medical theories about digestion and bodily "humors."

But seafood and cheese are much friendlier partners in Southern American cuisine, whether as char-grilled oysters or cheesy fish and grits. You'll also find cheesed-up mussels and lobster in France. Perhaps the most famous fish sandwich in America, the Filet-O-Fish, is gooed up by a half-slice of American.

After Wale’s tweet, an article by news site Billy Penn assured skeptical Philadelphians that salmon cheesesteaks do, in fact, exist.

“The way Philadelphians feel about salmon cheesesteaks — and whether they’re used to seeing the option on menus — may have to do with which neighborhoods they choose to hang out,” wrote Billy Penn’s Mónica Marie Zorrilla.

If people refuse to recognize a popular food invented in Philadelphia as authentically Philadelphian, chef Kurt Evans considers it ignorance.

Evans, co-founder of popular Detroit-style pizza spot Down North, had made salmon cheesesteaks at his former restaurant, Route 23, as a form of whole-animal cookery — using leftover salmon belly to make decadent sandwiches.

“People were all talking about that one tweet from Wale. He’s talked about that plenty of times before that — salmon cheesesteaks,” Evans said. “A lot of it is just people not being aware of the whole landscape of the city they live in.”

The salmon cheesesteak beyond Philly

Some Philadelphia chefs of color have discovered that the best way to gain recognition for salmon cheesesteaks is to exit Philadelphia.

“It’s funny,” Evans said. “But you can make so much money on cheesesteaks when you leave Philly. You can make money here, too. But the shops in Philadelphia are all white-owned — the ones that get all the recognition.”

Evans’ former partner at Route 23, Allen Young, moved to Norfolk, Virginia, to start a jammingly busy downtown shop called Major Phillie Cheesesteaks. His long-marinated salmon cheesesteaks quickly became one of his most popular items.

“When I first opened Major Phillie, people were like, ‘A salmon cheesesteak? What’s that?’ They weren't feeling it. Now, it’s my second best seller,’” he said.

Philadelphian Dion Alston moved to Dover, Delaware, to found a halal spot called Akhibachi’s serving ginger-garlic-sauced salmon cheesesteak — a dish that quickly landed him on the local news. In Buffalo, food writer Andrew Galarneau quickly hailed the salmon cheesesteak at that city’s Eleven as his new favorite “fish-based drunk food.”

And in Atlanta, West Philly native Derrick Hayes founded a quickly growing empire of cheesy beef and chicken and salmon. Big Dave's Cheesesteaks expanded from a gas station to two standalone restaurants and a roving food truck famed for lines down the block.

"The salmon is really a hot item right now, especially because a lot of people may not eat red meat," said Hayes, who first encountered salmon cheesesteaks in Philadelphia.

Closer to home, influencers like Lek helped propel the sandwich's popularity. The JL Jupiter video on seafood cheesesteak at New Jersey's Harvinskins was viewed more than 100,000 times, transforming it from corner spot to regional destination.

"He did a video, and now everybody wants it," said co-owner Gaylord. "Everybody has to have one on their menu."

She just wishes her late partner and fiance, Harmon Ford, could have lived to see the sandwich's acclaim. He'd concocted Harvinskins' version after trying one in Philadelphia.

"He passed it down to us, but he never got to see how popular it became," she said. "We're just trying to carry on his legacy."

Matthew Korfhage is a food and culture reporter for the USA TODAY Network's Atlantic Region How We Live team. Email: mkorfhage@gannettnj.com | Twitter: @matthewkorfhage.

This article originally appeared on USA TODAY NETWORK: Salmon cheesesteak? The real story of this Philly sandwich gone viral