Ask a San Diego local where to find the best Mexican food, and they'll probably say "Mexico". The border is only a 45-minute tram ride away and, contrary to public perception, is easy to navigate. After passing through an uninviting prison-style gate labelled "TO MEXICO", I fill in a simple immigration form, show my passport to an official and, hey presto, I'm in Tijuana.
I'm here to check out the local food scene with Derrik Chinn from Turista Libre, a company he started in 2009 to show visitors there's more to this much-maligned city than the headlines about drug cartels and refugees suggest.
As we drive through a ramshackle suburb skirting the border, he points out the original border wall made using helicopter landing pads from the Vietnam War and a new higher one that's been constructed. "September 11 changed everything," he says. "The border used to be a barbed wire fence and people would nip over to get a McDonald's."
We begin our culinary exploration at El Mazateno, a tin-roofed joint with plastic chairs and tarpaulin sides. Despite its no-frills appearance, it's packed with office workers, many of whom are tucking into its famous seafood tacos.
Chinn suggests the house special, a lightly fried corn tortilla overflowing with spicy shrimp, cheese and marinated chunks of red snapper. As someone who has the spice threshold of a toddler, I'm apprehensive. But my concerns are unfounded, its filling, gooey and flavoursome with just a subtle hint of heat. Washed down with cold, refreshing glasses of hibiscus tea, the whole feast comes to less than $14.
Our next stop is Telefonica, a gourmet food truck park that wouldn't look out of place in Portland or Williamsburg. Clustered around a communal outdoor seating area are brightly-painted trucks selling everything from ramen to french toast to octopus burgers.
"Tijuana has a hodgepodge of people from everywhere," says Chinn, "so you'll find cuisines from all over the world."
After sampling a delicious pork and morita pepper taco from La Carmelita, I meet owner Jose Figueroa, who like many of the chefs here is a graduate from Tijuana's Culinary Art School. He has another truck in San Diego and is one of a new wave of entrepreneurs with interests on both sides of the border.
Of course, the food scene here hasn't always been this sophisticated. During prohibition, Tijuana was a popular party destination for Americans, and its main drag, Revolution Avenue, was a tawdry strip of casinos, bars and nightclubs. Our last stop is a remnant from that time. Caesar's opened in 1927 and is famous as the creator of the Caesar salad, which they still make from scratch at your table in a large wooden bowl.
The crossing back to the US takes less than 10 minutes and on the return ride to San Diego I find myself sitting opposite a young couple from Texas. I ask if they've also been to Tijuana for the day. "Oh no," the man replies, "we just came down to the look at the wall."
According to chef Edgar Chong, Mexican cuisine is underappreciated in the US. "People often think of it as cheap, fast food," he says, "but we want to change that." Chong works at Puesto, a chain of modern Mexican restaurants that has two outposts in San Diego. We meet at its flagship eatery, an elegant two-storey venue in the city's former Police Headquarters. Like Figueroa, Chong was born in Tijuana and also attended the city's culinary school, earning a master's in Mexican cuisine.
We start with esquites, a popular street food dish of grilled corn mixed with lime, cheese, cream and chillies. Next is a flight of tacos that includes two award-winners – the chicken al pastor (chicken with melted cheese and a zesty pineapple topping) and the filet mignon (tender steak with avocado and a spicy pistachio serrano salsa). Served in homemade organic tortillas, they might just be the best tacos I've ever had.
For Chong, this is clearly a passion project. "I love Mexico and I love Mexican cuisine," he says. "I want to expose it to the rest of the world."
One place that should serve authentic Mexican food is San Diego's Old Town. Established in 1769, it's the site of California's first settlement but has morphed into a slightly theme park-ish tribute to the city's Hispanic heritage. Hidden among the giant sombreros and frozen margaritas are some gems, though, such as Tahona, a new restaurant specialising in the cuisine from Mexico's Oaxaca region. As well as serving homemade sopes and moles, it has a tasting room where you can sample more than 120 varietals of mezcal.
Mexicans born in the US often call themselves Chicanos and you can see Chicano culture in all its colourful glory in San Diego's Barrio Logan. After the city built an interstate through the suburb in 1963, the community lobbied successfully to create a park underneath it and paint its concrete supports with vibrant murals celebrating Mexican culture. The suburb is still the city's Hispanic centre and home to San Diego's oldest Mexican restaurant, Cuatro Milpas. This local institution has an almost permanent line outside, so if you're short on time, nip around the corner to Salud!, its tattooed hipster cousin, which serves equally delicious tacos and a wide range of craft beers.
Sitting on Salud!'s sun-drenched patio with a margarita and a hearty fish taco, it's hard to reconcile Trump's border obsession with the obvious benefits Mexican culture has brought to the US. Many San Diego restaurants rely on workers who commute daily from Tijuana and San Diegans regularly cross the other way for concerts and events.
Telefonica says it best. High above its huddle of gourmet food trucks is a large green billboard with a taco-wielding Trump and the message: "Food has no walls".
FIVE MORE CROSS-BORDER COLLABS
Bringing Mexican flavours to American beer, Southnorte infuses its creations with agave, hibiscus and chocolate at its brewery at Telefonica. See southnorte.com
Arguably Tijuana's most famous culinary export, chef Javier Plascencia has run restaurants on both sides of the border and now owns a hotel in the Valle de Guadalupe wine region. See chefjavierplascencia.mx
MUSEUM OF PHOTOGRAPHIC ARTS
Every year, in a joint exhibition, this museum in San Diego's Balboa Park exhibits the work of talented young photographers from San Diego and Tijuana. See mopa.org
Born in San Diego but raised in Tijuana, Priscilla Curiel opened a restaurant just north of the border that's gained a cult following for its birria de res (stewed beef shoulder). See facebook.com/tuetanotaqueria1
At this former naval training base turned cultural centre, Tijuana-born artist Hugo Crosthwaite has painted a series of touching murals highlighting the plight of immigrant Mexican families. See libertystation.com
United flies to San Diego via Los Angeles, Houston and San Francisco. See united.com
Offering sweeping bay views, the new InterContinental San Diego has three bars and an outpost of Del Frisco's acclaimed Double Eagle Steakhouse. See intercontinentalsandiego.com
Turista Libre offers public and private tours in Tijuana. Themes include food, craft beer and baseball. See turistalibre.com
Rob McFarland was a guest of United Airlines and San Diego Tourism.