It may be the best-kept secret on Broadway. Chula Vista, that is. The patio of La Costa Azul ("the Blue Coast") feels like any beach café on the Mexican coast. Except the family that runs it specializes in seafood cooked in the picante northwestern style of Nayarit and Sinaloa, the gritty-but-pretty mainland states roughly across the Sea of Cortez from southern Baja. (Mazatlán's the best-known beach town in Sinaloa. Nayarit is the next coastal state south.)

Costa Azul's owners must be doing something right: they have been a mariscos (seafood) fixture here for 25 years. Every time I've cruised by the strip this place is in, with its smoke shop and other not-so-glam neighbors, I've noticed folks going in and out of the restaurant. And this is no matter what end of the week.

So late one Tuesday afternoon, Carla and I walked into that sunny patio. A cool breeze fluted through the latticework, and beer pennants flapped away. "Pacifico." "Tropic of Corona." Yellow, blue, white. We sat at a table shaded by palm thatch. The chairs were strawbacks; the tables were solid, varnished wood. The waitress who brought us the menus said all the furniture had come from Sinaloa.

The menu was filled with seafood, of course, from oysters and mussels to shrimp, octopus, clams, abalone, and squid. But Carla -- she makes no bones about being a full-on carnivore -- decided on an appetizer of queso fundido with chorizo. "My dad always told us that the first chorizo in Mexico was made by Hernán Cortés himself," Carla said. "Actually, Papa made it the best. He added almonds, or wine, or green peppers."

What we got was like a cheese fondue, but in a long plate, with Monterey Jack melted around a brown island of fine-chopped chorizo. We shared. Unfortunately, the cheese didn't stay melted that long and turned to, like, chewing gum. But the chorizo gave it a tang, and with a scoop of an excellent dark-red salsa, I thought it made a great appetite stimulant. Carla wasn't so thrilled. "Not bad," she said. "Not over-greasy, good kick...but not enough. Too much cheese! My heart still belongs to Daddy."

Me, I wanted fish. I headed straight for a section of entrées called Lo Mero Mero ("the best of the best"), with dishes like abalone, lobsters, and whole fish. I bypassed the basic pescado frito in favor of pescado veracruzano (fish in the style of Veracruz). Anything from the Veracruz area on Mexico's Caribbean coast is likely to have flavors of tomatoes, onions, and olives, but I figured they wouldn't drown the grilled fish in a tsunami of sauce.

They didn't. It was a beautiful, big plate with an entire fish staring up at me -- head, fins, fantail, and all -- surrounded by salad, nicely spiced bendy fries, and a mound of red rice with a little Mexican flag flying on top. But it was the flesh of this fish that got to me. It obviously had garlic in there somewhere and was well-spiced. Best of all, it was unfishy, sweet and delicious. They had slashed the fish's sides. Guess that helped the sauce penetrate. It certainly made it easier to peel off the flesh. Yes, you had to watch for bones. I asked what species of fish it was. "Mojarra," the waitress said. I couldn't quite place it. "Your basic tilapia," Carla said. The waitress confirmed it. Oh wow.

Good old tilapia, the fish you see in those massive Salton Sea die-offs, right? Its big claim to fame is that it's one of those ancient, white-fleshed fish originally from Egypt, along with its close relly, the Nile perch. In the Holy Land, it's also known as "St. Peter's Fish": Legend has it that tilapia was the fish Jesus used to miraculously feed the 5000 on the Sea of Galilee. A tilapia was also the first fish in space -- taken for a ride along with John Glenn as an experiment in weightless fish farming. (Uh, question, Senator: When the water's floating, is the fish floating too?) In the last couple of decades, earthly aquaculturists have come to regard the humble tilapia as the miracle fish of the age. This little beauty is a plant-eater. 'Course you read about it going wild and eating other fish and even cannibalizing its own kind when it's introduced as an exotic species. They say it has totally destroyed Africa's Lake Victoria. On the other hand, it has become the fish to rely on for fish farmers worldwide.

At next visit, Carla was a little disappointed with her choice of entrée, the Filete Don Alfredo. Main problem: we both thought she was ordering a beef steak fillet, not a fish fillet. On reflection -- a mariscos cafe, duh. What turned up was a fillet of lenguado -- sole. And this was drowned in sauce, a thick mushroom mix "flamed with brandy." It was good, tender, fresh, but not terribly interesting.

In contrast, my aguachile (shrimp soup, a form of ceviche) arrived in a really big (nine-inch) black molcajete, the volcanic rock mortar bowl on legs that the people of Mexico have been using for, oh, 6000 years. Aguachile -- also an ancient dish that originated in Sinaloa -- contains onions, tomatoes, cucumbers, serrano chiles, and cilantro bobbing around in the briny shrimp stock with a dozen peeled shrimp. The brine was refreshing, cool, simple, spicy-hot -- history in a bowl. I could imagine the ancient inhabitants of Sinaloa sitting under palapas just like these, eating from a molcajete, just like this.

But back then, I'm told, aguachile was a paste -- not a soup -- that was spread across a cracker of sorts, probably something like those little Krispy Original crackers we got. What it really cried out for was a cerveza to soothe the hotness. But the horchata (a concoction of rice, almonds, and vanilla -- reportedly a hangover cure) that I had did a pretty good job of cooling down those (pant pant) chile burns.

Carla ended up ordering two carne asada tacos to get her meat fix. You could see her relief. She declared them the best she's eaten for a long time. I took a nibble and they were rico-suave.

Moments later our order of langostinos (Large crayfish? Small lobsters? Take your pick...) arrived, looking sleek as '50s Cadillacs in their red shells. Again the salad-frijole-rice sides came along for the ride. The 'stinos were great, nice and garlicky, especially their tail meat. My problem? Battling all those spidery legs and feelers. It makes getting to the good stuff, well, hard work.

Piping-hot corn tortillas were, as always, part of the deal. And I was impressed by how often the meseras -- the serving ladies -- came to replace those tortillas with more baskets full of steaming-hot fresh ones. In Nayarit and Sinaloa, it seems, heat matters.

But I was soon distracted when a waitress zipped by with this sizzling, delicious-looking plate loaded with meat and shrimp -- and delivered it to the couple right behind us. Damn. Great-smelling fajitas. I could hear them still cooking on their black iron hotplate. I wanted them.

So -- what the heck? -- back we went the very next day. I ordered up a fajitas mixtas, with the shrimp, beef, and chicken all in together, served with corn tortillas and the usual garnishes. Don't get me wrong. I appreciated all the other dishes...but this, this was love. At first bite. Half the pleasure is that evil black plate arriving, hissing and snapping at you from the table. The other half is the actual eating. Those grilled flavors of the three meats and the peppers and wicked, slick, half-burned onions. The meats were rapier-hot, fresh, tender, and so tasty. No resistance. (Yeah, I've had 'em old, cold, and leathery elsewhere.) The secret is in a lime marinade that actually "cooks" the skirt steak (fajita) before it ever sees a flame. Overnight is good, two days later is better.

Ceviche, too, is one of those dishes "cooked" by lime juice, which we had on another visit. Ceviche can be any sort of seafood. We chose the ceviche de pescado as a seafood cocktail (though we could have had it, or ceviche de camarón, with chips, or on a tostada, Baja-style). Our ceviche, served in a tall sundae glass, had chunks of tomato, cucumber, and purple onion in the briny mix. We pumped on additional zest with some salsa huichol, a hot sauce from Nayarit. Think "Tabasco plus flavor." It features a smoky-flavored chile called the "jingle bell" or "rattle." That's because the dried cascabel seeds rattle in their pods. (Salsa Huichol is also in a dish here called camarones cucarachas, "shrimp cockroaches." They're basically shrimp, pan-cooked in huichol sauce.)

We couldn't resist just one more regional foray. This time, I ordered the camarones culichi (meaning shrimp cooked in the style of Culiacán, the capital of the state of Sinaloa). It's baked shrimp in a béchamel sauce turned green by seared bell and Anaheim peppers, with a dash of paprika and some subtle- flavored melted cheese that's hardly noticeable. Carla opted for the dish that bears the owner's name. It's called camarones Gloria's [sic], "bathed in her special sauce" -- béchamel plus cilantro. Actually, the two are pretty similar. Carla loved them both. For me, they were mild, and mildly interesting.

Ironically, though, the thing Carla enjoyed most was her pile of refried beans and melted cheese. She was sure she detected an authentic pork lard flavor in there. "They taste slow-cooked. No scorching. No tough bean skins. Just like my mamacita used to make," she said. "The longer the frijoles stayed simmering in the cazuela [the casserole pot], the better they tasted."

Before we left we splurged on a buñuelo, a big, crisp, sugary fritter-tortilla that goes down well with coffee (although our coffee here was instant, and not the greatest). Traditionally, buñuelos are Christmas treats made from a yeasted donut dough, sometimes with a tweak of anise, deep fried, then soaked in a syrup of brown sugar with cinnamon. Yum. Here, we cracked away at this quartered disc till we could eat no more.

Of course, La Costa Azul also cooks up the full range of Mexican standards, but go for their regional specialties. To be honest, I'll mainly be back to enjoy the feeling this patio tropical gives you. Yes, there's plenty of inside dining. But outside, you get that strange feeling of being somewhere else. I know, we're talking Broadway, Chula Vista. But I'm thinking Mazatlán -- without the airfare.

ABOUT COSTA AZUL

"My mom is the hardest-working woman in South Bay," says Julian González Jr. He's the last of Gloria González's children working full-time at the restaurant, though many in her extended family lend a hand. "She keeps the place going," says Chris, her nephew, who says he has worked here his whole life. "She holds us together."

It has been a 25-year labor of love for Gloria González, who has been overseeing the restaurant on a daily basis since she and her husband, Julian Sr., opened in 1981. He hails from Mexico's Nayarit and Sinaloa regions; she from Tijuana. Their four kids grew up helping out in the restaurant, though three are now in the real-estate business.

Gloria didn't know much about cooking and running a restaurant when they started out, but her husband "taught me everything," she says. Then in 1990 the couple divorced, and newly ex-husband Julian started up his own "Costa Azul" in Imperial Beach. Gloria carries on here in Chula Vista, with help. "My kids have been helping out since they were ten years old," she says. "They all learned to cook, serve, clean, everything. Their father taught them how to work. It has certainly helped them. I hire a lot of young people who don't want to work."

She says it's also a hard-work kitchen because virtually nothing is pre-prepped. "We are not fast food," says Gloria. "Except for beans and rice, which we prepare in the mornings -- never from cans -- everything is prepared from scratch to order."

The most popular dish, according to Julian Jr., is siete mares, a broth containing fish "from the seven seas" -- including shrimp, octopus, clams, abalone, squid, and fish. It's considered major nutrition and great for hangovers. "Saturday morning this place has a lot of guys come in for siete mares," says Julian. "Then on Sundays, around two p.m., we're really busy. That's when everybody gets out of church and brings the family."

His cousin Chris disagrees on what's most popular. "It's camarones Costa Azul," he says. "They're the shrimp stuffed with cheese and crab and rolled in bacon. People love them. They're probably the most famous thing we have. That and aguachile."

This restaurant is closed.