Last November strange flyers began to appear around Burlington. They were swooshed with a chile pepper and stapled to corkboards on Church Street bars, slipped under windshield wipers, and looped over doorknobs with a rubber band. "Sunday menu no.1," read the sheets of paper. "Minimum of 2 items per order please/delivering every hour 11 to 5pm." The business was called, mysteriously, Big Chile Republic. No address, just a phone number and three items on the menu.

At first, everyone pretty much ignored this guerilla marketing. Then a few adventurous customers began to order the burritos and tacos and discovered the stuff was actually good. Really good. But what, and who, was Big Chile Republic? And, with no storefront, where were they cooking up these tasty tortillas?

I vowed to find out. But first, I ordered from the online menu and devoured the pollo de arbol tacos, verduras y frijoles blanco burro and recado tacos de carne asada. Then I managed to convince the pair behind the Republic -- Chris Hechanova and Andrew Lawrence -- to talk to me about their new enterprise. No, I couldn't come to their kitchen, they said, but we could meet over coffee in town. "Hmm, what's wrong with their kitchen?" I thought. Though disappointed not to get a peek at their stove, I agreed to the neutral territory and put the guys on the grill instead.

The underground delivery service got fired up late last fall after Hechanova, 31, and Lawrence, 22, had stirred the idea around while cooking at Burlington's Iron Wolf restaurant. "It wasn't a really crazy notion," says Hechanova. He moved to Vermont from Chicago in 2002 to study at the New England Culinary Institute (NECI), and started looking for good Mexican food in the area. "In Chicago, there are amazing Mexican dives, a dime a dozen, as many as blues joints," he says. "Around here -- and I know this may sound arrogant -- there was nothing even close."

Hechanova also discovered that he couldn't study at NECI and support himself simultaneously, so he opted to cook full-time, beginning at Smokejacks before gigs at O and Iron Wolf. For months, the idea of a new Mexican place simmered in the back of his mind. Having worked at Robert Redford's prestigious Sundance Resort in Utah and other top restaurants, Hechanova had the experience, but not enough capital, to launch a venture of his own.

Enter Andrew Lawrence, a recent graduate of the University of Vermont. The two began to cook up a plan to bring more "south of the border" to, well, south of the Canadian border.

"I'm kind of a goofball, and Andrew's kind of a goofball. He's got a car, and I've got the background and I love cooking," says Hechanova. "So we started to get creative about doing something with zero capital."

The pair spent a couple weeks coming up with a name, whispering conspiratorially as they worked at Iron Wolf. Then, Hechanova designed the first menu: adobo chicken tacos, braised black bean and chickpea burrito, and marinated beef burrito with lime creme fraiche. He planned to cook everything in his apartment in the Old North End.

Because they were still working full-time, Hechanova and Lawrence decided to offer the takeout cuisine only on Sundays. The week before opening day, November 9, Lawrence distributed 600 menus around town. They shopped for tortillas, tomatoes, beans, cilantro and more, and stayed up all Saturday night prepping the ingredients for their first hour of deliveries at 11 a.m. Then they waited for the phone to ring -- and waited some more. "Not a single call," says Lawrence with a laugh.

"We were OK with it, because our overhead was zero," says Hechanova. "I basically figured that we'd just be eating rice and beans for a while, and was pretty confident that it was only a matter of time."

Sure enough, by week two -- and menu two; they change every week -- the fledgling entrepreneurs received an order for pork burritos. Some curious friends stopped by to try out a few dishes. Big Chile was getting warmer.

The day after we first meet, Lawrence does show me around their kitchen, which in fact has nothing wrong with it. As narrow as a ship's galley, the space is immaculate and stacked with professional All-Clad pots and Calphalon pans. An adjacent pantry area holds crates of tomatillos, avocados and tomatoes on a wire shelf. Hechanova and Lawrence pick up fresh herbs at Price Chopper; their other ingredients come from local farmers, Burlington Foods and a Mexican specialty distributor in New Jersey.

Tacked to the wall of the kitchen, just below a giant map of Chittenden County, is a commercial catering license from the Vermont Department of Health. Shortly after taking their first orders, Hechanova and Lawrence arranged for an inspection. "We get regular calls now from the health department ordering food," says Lawrence. That should tell you something about their score.

Big Chile Republic has several other regular customers who began calling around the same time earlier this year; some of them send comments via email. "I just tried my first burrito from you folks," writes one. "I was blown away by how delicious it was. Finally, Burlington has a Southwestern alternative that is original, delicious and healthy. Keep up the good work. I'll be ordering again from you soon."

One night, when the two entrepreneurs were at Three Needs celebrating Big Chile's launch, they met Zack Amaral, a part-time carpenter and pizza courier who offered to help deliver orders when things got busy. And they soon did. Hechanova and Lawrence scaled back their work at Iron Wolf, and eventually quit in order to run their Republic Sunday through Thursday nights. "People have asked us for Friday and Saturday, but I didn't want to compete with pizza places," says Hechanova. "Plus we need time to replenish -- both ourselves and our supplies."

While Hechanova does all the cooking, Amaral and Lawrence divvy up the deliveries; all three have developed a unique rapport with their growing base of customers. "People get really, really excited for the Big Chile Republic," Amaral reports. "Plus it's much more personal than just delivering a pizza."

"The 'matriculation' rate week after week is unbelievable... people invite you into their homes, and you meet their dogs or their children or their significant other," adds Lawrence. "We're not like the Cable Guy, but on the other hand, it's nice to be able to know someone beyond the regular point-of-sale purchase."

Seeing the same names every week on their caller ID, says Hechanova, "makes our job have more meaning... We're actually creating bonds with people."

Not everyone is so happy, however. "Our guerrilla marketing techniques sometimes offend people," Lawrence admits, referring both to the paper waste and to the intrusion. One Burlington resident was more to the point: "I do not appreciate your advertising method of sticking a menu on my door. Please keep your garbage away from my door."

In fact, Hechanova and Lawrence are now turning toward more eco-friendly advertising approaches. Since adding Tuesday and Wednesday lunchtime service about a month ago, they've been doling out free samples to local businesses. They also increasingly rely on the Internet as a way to update customers. Since No. 1, the menu has evolved both stylistically and substantially, with sharper graphics, four choices instead of three, as well as more "additions" such as guacamole and jicama salad, and Mexican drinks.

Entrees run at around $5.50. The food is consistently fresh, innovative and irresistible. I nearly canceled some travel plans when Lawrence told me what I'd be missing during my time away: deep fried stuffed poblano chile with lump-meat crab; roasted chicken with tomatillo salsa, pickled onion and radish; pulled pork with spicy corn and orange salsa, hominy and roasted Serrano chile; squash with pear-coconut sauce.

Lawrence plans to post past menus on the website so that customers can remember favorite items. And they may all appear on one giant menu someday, if Big Chile Republic becomes a sit-down restaurant. Could it happen? One customer warned, "Don't get a storefront or a space downtown! Keep your overhead down and keep the whole underground vibe going. It's totally working, you're starting to develop a cult..."

After paying the rent, Hechanova and Lawrence tuck away the rest of their money for the business' future. But they admit that they're looking around for a place cool enough for Big Chile Republic. "Before, it was like, 'Oh, we made $100, let's go out and drink!'" says Hechanova. "But now we're more responsible. We're a real entity. This is not a joke."