It is common knowledge among habitues of the Yue Kee mobile kitchen that one should never, ever, simply walk up to the truck's open window and expect an order to be speedily noted and prepared.
It might help if you speak Cantonese. But a simple call to Bi Pang's cell phone is really all that's needed.
"Twenty minutes!" she'll bark. Then she'll return to her brusque flurry of packing and organizing the mountain of orders for a lunchtime rush that gathers impatiently on the shaded sidewalk of South 38th Street, across from the Wharton School.
But some people learn the hard way, like the fellow who waited 15 minutes in line behind me before finally giving up in exasperation. He whipped out a cell phone and called Pang, just five feet away, who promptly took his order for ginger chicken and string beans with beef before hanging up: "Twenty minutes!"
I suspect there are two reasons Yue Kee has flourished here since 1983 despite an inefficiency bordering on rudeness that makes it the "Soup Nazi" of Chinese trucks. The first is that Pang's husband, Tsz Pong, expertly wok-cooks each order fresh in the back of the truck, and his food is worth every minute of the wait.
The second reason is that Yue Kee's ancient Grumman truck is so dilapidated - a beat-up metal hulk that croaks like a lawn mower and looks as if it just returned from a tour of Iraq - that it attracts few newcomers, allowing the couple to focus on loyal customers who know better than to judge them by their cover.
As if to throw those newbies even further off the scent, the handful of things Yue Kee does not do well - wonton soup, egg rolls, and stir-fries with deep-fried chicken - are exactly the bellwethers that most non-Asians typically order.
After several memorable lunches there over the last six months, however, I've come to believe that those few weak dishes are simply part of the charade. Yue Kee is not the grungy, surly, excruciatingly slow food truck it first appears to be. It is one of the better Chinese kitchens in the city.
I find myself with regular cravings for the Beijing "hot noodles," which are essentially a Chinese spaghetti bolognese with a fiery, complex spice. But there are so many other dishes I also love.
The ma pao tofu delivers a sharp and punchy spice tweaked with the rich saltiness of dark soy, but this classic Szechuan dish is also a study in textures - crumbles of ground pork playing against the silken softness of tofu and the crunchy snap of shredded bamboo.
Unlike so many other low-end Chinese venues, Yue Kee's food appears to contain zero filler (e.g., no shredded celery or carrot), focusing instead on a few principal ingredients. Its sauces are not the usual dull variations on gloppy Brown Sauce No. 1, but are vibrant and remarkably distinct.
The ginger chicken might aptly be renamed scallion chicken, because it appears to be little more than a mound of tender white meat tossed with a fistful of crunchy onion greens. But a swelling heat in the clear sauce rings brightly with ginger spice. The chicken with string beans is a look-alike dish, but it tastes completely different, the heat-blistered beans lending the tender meat a shade of nutty garlic sweetness.
Beef with eggplant in black bean chile sauce is another simple winner, setting the tender meat against meltingly soft half-moons of violet-skinned Asian eggplants.
I wasn't thrilled with the unnaturally fluorescent pinkness of Yue Kee's goopy Szechuan sauce, but I couldn't help but notice the delicate snap of the superbly fresh shrimp it covered. Those crustaceans were better displayed, perhaps, in some of the truck's more complicated stir-fries, for example, a subgum fried rice that matched tender shrimp with the crunch of chopped veggies and nuggets of roasted pork.
Even better were the Singapore noodles, which my esteemed but finicky Food section colleague, Rick, declared the best he'd eaten in the city. With their snappy threads of thin rice noodles permeated by the fragrant jab of toasty curry, the pop of pink shrimp, and chewy shreds of sweet pork, I'd have to say I agree.
I found myself compelled to order and reorder so many of my favorites here that it took an extra dose of hunger and reportorial zeal to explore the farther reaches of Yue Kee's extensive menu. But it did bring some rewards, chief among them the dish that is alternately spelled (depending upon which menu you read) "pork billy" or "pork belly."
Made from a recipe handed down from Tsz's father, this is essentially thick slices of Chinese bacon, steamed with leaves of medicinal herbs to a tender sweetness perfumed with Asian spice. The sparerib tips in black bean sauce are another specialty least likely to win beauty contests, but I liked them, too, each nib of bone hugged by a ring of tender beef glazed in the subtle ferment of a light black-bean gravy.
For connoisseurs of old-time chop suey-house cuisine, Yue Kee also makes a standout egg foo young. It was a generous serving of two disc-shaped omelets filled with sweet onions, soft morsels of chicken, and a thick-but-not-sludgy brown gravy that conveyed the perfect effect of salty richness.
Of course, one of the richest treats of dining at Yue Kee is the sheer value of its food, which tops out at $4.50 a dish. It is, after all, a truck. But when my order was finally prepared and Pang eventually handed over the bill - just $29 for eight dishes and three drinks - I was momentarily stunned by the astounding cheapness of this food.
Then I strolled up to the base of the Locust Walk bridge nearby, where there was a cluster of well-placed picnic tables. Birds were chirping. Students hustled by to class. And we opened our bags of Styrofoam-boxed treasure, and feasted like kings.
On July 10, Craig LaBan dines at the Jersey Shore.
Contact restaurant critic Craig LaBan at 215-854-2682 or email@example.com. Read his recent work at http://go.philly.com/craiglaban.