Take a taco shell, throw in some galbi short ribs, add a dollop of ssamjang sauce, give it a California vibe, and you’ve got something new and hot in South Korea.

Sid Kim — born here, raised in Los Angeles — found he never quite blended in in either place, so he did the natural thing. He opened a Mexican restaurant. Well, Ko-Mex, actually. The central Seoul district of Itaewon, once a gimcrack preserve of GIs and expatriates, is now awash in restaurants that give new meaning to the word “fusion” — starting with their owners.

“We call it the kyopo renaissance,” said Kim, one of the owners of Vatos Urban Tacos, using a local word for people who are ethnically Korean but were born or raised elsewhere.

Many other kyopo restaurateurs have arrived in Itaewon, helping transform a neighborhood that Koreans had for years been giving a wide berth. With its proximity to a huge U.S. Army base — the military facility is at the end of the main street — and its seedy nightlife, this area was long associated with drunkenness, crime and speaking English, a place where foreign men went on the prowl along a stretch of road still called “Hooker Hill.”

These days, going to Itaewon is a totally different experience — and one that Koreans increasingly want to be a part of. A K-pop star even released a disco song called “Itaewon Freedom.” (“Itaewon freedom, those brilliant lights, oh oh oh.”)

Sid Kim, one of four founders of Mexican restaurant Vatos in Seoul, said that “now it’s cool to be kyopo,” or ethnically Korean but raised elsewhere. (Shin Woong-jae/For The Washington Post)

The neighborhood has become known as the place to get great food in stylish surroundings, with popular TV programs showing Koreans on dates here — inevitably prompting a stampede to the restaurant du jour.

Many of the restaurants were started by kyopo. There’s Vatos, offering dishes such as kimchi carnitas fries — incorporating Korea’s ubiquitous pickled cabbage dish. And there’s Linus’ Bama Style BBQ, run by Alabama native Linus Kim, and Lobster Bar, started by brothers Chris and Young Kwon from Fairfax, Va., along with Londoner Paul Jung. There’s also Left Coast Artisan Burgers, the upscale Libertine Bar and Kitchen, and Rye Post gourmet sandwiches.

“A lot of Korean Americans are returning here because of the success of Korean Americans in the U.S.,” said Kim of Vatos, citing Roy Choi, the “godfather” of the Los Angeles Korean taco truck, and David Chang, who started New York’s famous Momofuku restaurants.

The metamorphosis of Itaewon is by no means complete. There still are many tacky souvenir stalls and basement dens plying knock-off designer bags. But there is no question that this area is changing, and rapidly.

The transformation has a lot to do with South Korea’s economic rise and the increasing frequency with which South Koreans travel abroad. And the changes are in no small part linked to the arrival of people such as Kim.

Sid Kim returned to Seoul in 1996 to study, and afterward he opened a range of businesses, including a hugely successful English-language cram school. But at the end of 2011, the year that “Itaewon Freedom” came out, Kim and two partners sensed a tide of change and opened the first iteration of Vatos in a small side alley. Since then, Vatos has flourished, moving into a huge new space above the main drag and opening three other branches.

“We act as a bridge between both cultures,” Kim said over burritos on a recent day when asked to explain Vatos’s broad appeal. The clientele at his first restaurant was 80 percent expat and kyopo, and 20 percent Korean, but now it’s the other way around, Kim said.

“It’s really hard to cater to both tastes, both types of service,” he said.

Take service. Koreans, used to collecting empty beer bottles on their tables, would be offended by the American practice of waiters’ clearing away used plates and empties while a table is still occupied. They would think the restaurant was trying to kick them out.

Across the street, Linus Kim, a 40-year-old Korean American who was raised in Birmingham, Ala., was stirring what seemed like a ton of raw sugar into a huge pot of sauce. “This was a really seedy part of town, and Koreans were scared to come here,” he said, looking all hipster with horn-rimmed glasses and retro cap with a cartoon pig on it.

A “BBQ hobbyist,” he had been working in the film industry in Los Angeles but wanted a different career. He came to South Korea to help a friend make a television cooking show, which led to his cooking barbecue for private parties and then to pop-up restaurants.

He went back to the United States and studied with “grand masters” in Illinois and Oklahoma, and even became a certified barbecue judge (there is such a thing).

Then he opened Linus’ BBQ in an alley behind the main street in June, complete with a covered patio area with M.A.S.H-style olive green tents and Red Cross flags. He likes to see how many customers get the Korean War reference.

Linus’ gets many military personnel for lunch, their uniforms in perfect harmony with the decor.

On the menu are platters of pulled pork and brisket, served on military-style stainless steel trays and made for Korean-style sharing. There’s smoky mac and cheese, deep-fried ribs and “skinny ass” fries.

Paul Jung and the Kwon brothers also decided to introduce a relatively rare foreign food to Itaewon, opening Lobster Bar. Like Vatos, Lobster Bar started small, with a tiny place in an alley, hoping to change the perception that lobster was a luxury food.

Once that venture gained steam, they built up the courage to open a big restaurant in prime real estate on the main street in November. A bright red shipping container houses the kitchen, giving the place a street food feel.

“A lot of people are coming in and eating lobster for the first time in their lives,” said Jung, 31. “They don’t even know how to crack it open.”

About 80 percent of the clientele is Korean, people who are curious to try the exotic crustacean, brought in from Maine or Canada. The most popular dish, the restaurant’s operators say, is the lobster grilled cheese, a creation geared to the local market.

This wave of first-time restaurant owners is changing not just Itaewon, but also the kyopo experience. Many describe feeling not completely American in the United States, but not completely Korean in South Korea, where they are often criticized if they speak less-than-perfect Korean.

“We’ve reached a critical mass now,” said Sid Kim, getting ready to return to his office after the Vatos lunch rush. “When I came in 1996, it was hard to be kyopo. Koreans discriminated against us. But now it’s cool to be kyopo, in America and here. It’s our time.”