Throw away the spongy, characterless bread of your typical hero. Replace it with a crusty, fresh-baked French baguette about eight inches long. Heat up the roll in a broiler oven and rip out the soft, white insides. Spread homemade mayonnaise in there. Instead of mushy tomatoes, watery lettuce and limp white onions, load up the warm roll with slices of cool, crispy cucumber, slivered sweet carrots, strips of fiery jalapeno and a bouquet of green cilantro leaves. Now comes the meat. You may have aromatic pate chaud (remember that Vietnamese cuisine, even snack food, has long been influenced by the French), shredded chicken, barbecued pork or some combination of all three; meatballs with spicy tomato sauce, charcoal grilled pork or any of a number of choices. Sprinkle a little soy sauce on top, a dash of mixed salt and pepper, wrap it in thin white paper and you've got the addictive banh m thit, literally "bread meat," but otherwise known as a sandwich.

The cost of this healthy gourmet fast food? At most of Houston's banh m shops a basic sandwich is $1.50; combo sandwiches run a little higher at $2. If you buy five, you'll generally get one free.

There are small banh m places tucked into strip centers and shopping malls in the sprawling Asian districts of downtown and southwest Houston. They vary from simple, white-walled, self-serve lunch counters with cafe curtains to dark, smoke-filled dens populated with thin young men eating black herb jelly and playing video games. While the sandwich menu and decor may differ, almost universally they play thunderingly loud Vietnamese disco music.

My favorite Vietnamese sandwich shop isn't all that close to where I live; it's not like walking around the corner. Instead, I get in my car and drive downtown six or seven miles to Givral's Sandwich Shop on Milam Street. If I'm in a hurry -- and obviously the hurry couldn't be much of one if I'm driving 14 miles roundtrip for a sandwich -- I order a shredded chicken to go and end up with shards of toasted bread crust and little bits of slivered carrot and jalapeno all over the car, remnants of a true happy meal.

Actually, it's not a good idea to be in a hurry in such a place. There's usually a line -- parents with small children, businessmen, working people, a priest, students in baggy pants and hip haircuts -- and the business of assembling these snacks can be slow, even slower if, to go with the sandwich, one orders a Vietnamese coffee, fresh squeezed orange juice or a salty-sweet lemonade (actually a limeade). The tropical fruit shakes -- durian, papaya, mango or avocado, to name a few flavors -- are refreshing but also require patience. Those on the run can grab a canned coconut drink, basil seed drink or pennywort drink from the cooler. My personal favorite is the canned guanabana juice.

The coffee served at many of the banh m shops -- called French coffee and well known to fans of full-service Vietnamese restaurants -- is a revelation in itself. The potent black liquid drip, drip, drips slowly through a small metal filter into your cup. Traditionally in Houston, Vietnamese coffee shops and restaurants use New Orleans French Market coffee with chicory. Trying to hasten the drip process by shaking or bouncing the hot metal filter usually only results in your getting your fingers burned. Have patience. Unless you say otherwise, the bottom of the cup is charged with about 1,000 calories worth of super-sweet condensed milk. Ask for your coffee iced, and you have a killer of a coffee shake.

Cast your eye about the place in search of other exotic delectables. Arrayed around the counter at Givral's, as well as at most other banh m locations, are sweets such as cream puffs, cassava or banana cake, tamarind seed candy, pudding made with fresh corn, banana fritters with sesame seed, little cups of sweet red beans and rice with coconut milk, longan fruit, glasses of green jelly strings and wrapped candles in the grabbing colors of green, pink and yellow made with tapioca and mung bean.

There are also savory delights in plastic containers: vermicelli rolls (banh cun) with peanut or fish sauce and delicious salads with translucent dumplings and slices of rolled steamed pork (gió) that taste like sophisticated bologna. Sometimes you can find packages of sticky rice with shredded chicken and sliced sausage, containers of shredded dried beef -- which is identical to a version of dried beef particular to northern Mexico -- and little bags of dried flank steak marinating in chile paste.

While there are basic types of banh m thits, each shop has slightly different offerings. At Banh M Thanh Ni -- which translates as Inner City Sandwich, though it's located in the far southwest on Bellaire Boulevard -- the pork meatballs (xi mai, sometimes translated as "meat loaf") are intensely garlicky and more like ground pork dumplings. The shredded chicken (gà) is white meat only. In other shops the xi mai comes in a deliciously tangy tomato sauce (notably at the dark, smoky video parlor named Saigon Cafe at 2902 San Jacinto) and the shredded chicken is dark and white meat and sometimes a bit of gristle (as served at Givral's on Milam). A second Givral's Sandwich Shop at 9308-A Bellaire Boulevard in the Metropole Center specializes in slices of sweet, baked ham. And while it's often not listed on the menu, most banh m shops also make sandwiches with tender, juicy thit nuóng, or charcoal grilled pork.

There are, naturally, some exotic-looking lunch meats at the buffet counter that taste fine but remain a mystery, such as the crunchy, cellophane-like, white-ribbed gi th, which according to my Vietnamese dictionary translates as "beast's foot." Asking the counter clerks for guidance isn't much help. They're busy, and would prefer you order something more familiar to your taste. It's reasonable to keep in mind, however, that the better-known, standard-American lunch meats are often filled with animal parts most of us would rather not know about.

These days the banh m menus, typically up on the wall, usually have subtitles in English. While the translations may not be all that useful, at least you get a general idea. (In one shop I saw a reference to gi, the bologna-like pork, translated on the menu as "frozen meat sandwich." Well, okay, I thought, that might be good. It was warm, not frozen, and it was excellent.) Generally banh m shops also serve a selection of hot dishes on plates or in bowls, and usually there are color pictures of those to act as guides. Such dishes are divided into two categories: rice (cóm) or vermicelli (bn). Givral's on Milam is relatively friendly to non-Vietnamese speaking patrons, but still leaves many items on the menu untranslated. Some cafes aren't prepared for customers who don't speak the language. Try French. The adventurous, who don't need advice anyway, will just point, pay and enjoy.

Givral's Sandwich Shop, 2704 Milam, 529-0462;
Banh M Thành Ni, 9284 Bellaire Boulevard, 779-1833.

Givral's Sandwich Shop, Banh M Thanh Ni:
mixed meat sandwich ("Special") or charcoal grilled pork, $2;
other single meat sandwiches, $1.50.