To many people walking through Chinatown, the dank gray staircase descending into the earth beside the parking structure at 11th and Race Streets is not exactly an enticing invitation to lunch. Unless they know about Tasty Place.

Framed by a grimy yellow awning and fingerprinted glass doors, this corridor is mostly known by savvy shoppers as the passage down to Asia Market (inside the "Chinatown Mall"), a sprawling subterranean emporium where fridge cases are brimming with exotic greens, multiple kinds of tripe, chicken feet and black-skinned chickens for soup, and a seafood counter fronted by bins of writhing eels, snapping crabs, and a grid-covered cage of still-croaking frogs.

Cavelike and utilitarian, this market has what you might need for jellyfish salad, but doesn't cater to the niceties of touristic browsing. The public restroom here is a horror, so take care of that before you visit. But you will want to visit. That's because of Tasty Place, a tidy nook of round formica tables that glows like sunshine at the rear of this fluorescent-lit basement, where 63-year-old master chef Simon Sei has been stir-frying his way into the bargain-hungry hearts of Chinatown regulars for nearly 20 years.

There are places aboveground that do a similarly fine job on these common Hong Kong-style dishes. But trust me: Tasty Place's devotees will be here snug below ground eating salt-and-pepper chicken wings during the apocalypse.

Those juicy wings are so good, marinated for a day in ginger and scallions, then wok-fried inside a cornstarch crust that crackles with edges that grab chile rings and salt, they're likely to soon become the object of wing-o-phile pilgrimages to the underworld.

And fittingly for the subterranean locale, I can thank an undertaker for unlocking the many secrets to Tasty Place's charms. Jayson Choi, nattily dressed for business in dirge black, settled into the table next to ours on a lunch break from the family's funeral home at 12th and Vine Streets and kindly took it upon himself to be our guide.

He and his family were eating a big pot of the "house soup," a daily cauldron Sei concocts for 50 cents a bowl from pork bones and a rotating roster of spontaneous add-ins — corn and other veggies that day, but Sei also occasionally adds chopped apples, ginseng, or green and red radishes. Choi waved us first-timers off the home-style house soup in favor of Sei's simple take on wonton, a delicate broth steeped from whole chickens that came brimming with dumplings wrapped in skins so sheer I could see the pork stuffing inside. There was also a lesson in the "ho fun" variations, the wide rice noodles tossed with tender flank steak that Choi ordered for us both "dry" and "wet." It was essentially the same dish, but rendered completely different with the addition of a juicy sauce, with greens adding verdant snap to the oyster-sauced gravy, but more intensity from the dry version accented by crunchy sprouts and pungent scallions.

"Every sauce here tastes a little different," says Choi, paying the ultimate compliment to the Kowloon-born Sei, whose Cantonese-style approach has been honed over 40 years of creating each dish from start to finish in one frenetic yet controlled dance at the wok. The food would taste completely different without him — though there's little risk of that. Open for nine hours every day, Sei has cooked every dish without a vacation for as long as he can remember. ("I've got 12-year-old twins," he says. "I'm saving for school.")

I was ready to explore the vast 159-item menu. But not before the undertaker's greatest gift: advice on how true Chinatowners doctor their ho fun — with a splash of red vinegar and a squirt of sriracha hot sauce.

Such a simple tip, but life-changing for an aspiring noodle expert, like learning for the first time that french fries are better with ketchup. The addition of vinegar and a little heat took already impressive flavors and transformed them into pop-up 3D. The nutty warmth of sesame oil used to marinate the beef became more pronounced. The five-spice swirling through the Chinese-style satay gravy (for beef noodles) became more vivid. The curried powder for Singapore noodles gained an extra-fragrant punch, punctuated by the most delicate shrimp and bits of roast pork edged with pink anise sweetness. A sauce made from rehydrated dried shiitakes for chicken rang with extra umami depth.

The trick wasn't universal. The ginger and scallion noodles, wheat noodle threads glazed with just a tint of oyster sauce and radiating the sparks of ginger matchsticks, was better on its own. But the vinegar splash was essential for all the rice noodle dishes — especially the odd "needle" noodles, shaped like inflated bean sprouts, giving chewy bounce to the snappy shrimp and pork.

One should also take note of the elegant hand Sei has with more delicate ingredients. His velvety white seafood-tofu soup weaves complexity from contrasting textures and soft-spoken flavors, the silky tofu and pristine broth a pale canvas for snappy pink shrimp, the briny spring of fish cake, the chew of rehydrated mushrooms, the spicy green crunch of scallions.

Sei's touch with fillets of flounder was particularly memorable. Marinated in a sesame-tinged haze of cornstarch and egg white, those meaty wok-fried fillets were fantastic alongside snappy pods of big Chinese okra, and even better layered between tubes of meltingly soft Asian eggplants turned dark, sweet, and tangy in a glaze of garlic sauce studded with black beans.

He's so deft with fish, I'm eager to one day taste what he can do with more luxurious ingredients. But with a humble price ceiling of $10 a dish, and ever aware of the cost-conscious expectations his choice location in Chinatown's underbelly brings, he offers an ideal solution for this BYO town: Buy your own lobster, crabs, or whole fish next door, and he'll cook it for just a few dollars.

"I'm next to a market, you know," Sei says, "so everything is, like, fresh!"