In Austin, you can get a breakfast taco anywhere and everywhere. Here's the ultimate guide.

If you drive around Austin, you will notice something, and I'm not talking about the rotten traffic. You will see banners that read "Now Serving Breakfast Tacos." Mind you, these are outside not only Mexican restaurants, but they're also at coffee shops and gas stations, burger stands and bars. You can find breakfast tacos at Matt's El Rancho in Austin-Bergstrom International Airport; you can find them at the Texas Capitol. Over Shiner Bock beers one night, we can argue about Austin's signature dish - whether it's barbecue or Tex-Mex or (please, no) some sprout-and-veggie delight - but everyone, in every corner of Austin, seems to be getting in on the breakfast-taco business.

Like the best street food, breakfast tacos are easy to make and hard to mess up. For less than $2, you get a warm tortilla filled most commonly with eggs, meat, and cheese. This is prime morning-after grub, and in a town of college students (and adults acting like college students), that's no minor point.

These days, I live in New York, the self-proclaimed culinary capital of the world, where I could sooner find an affordable loft full of attractive single doormen than a breakfast taco. So on a recent trip back home to Austin, I plotted an extensive breakfast-taco tour. My goal was to eat as many tacos from as many places as I could handle. I'll do anything for research - and for melted cheese.

Thursday, 6 p.m., Taco Xpress
One thing about breakfast tacos is that the name is merely a suggestion. Breakfast tacos are eaten all day and late into the night. After my plane landed at five p.m., I bought a classic egg-­bacon-and-cheeser at this famously folksy joint on South Lamar - think flowers potted in bathtubs, Christmas lights year-round, and signed photos of Willie Nelson near altars to la virgen. The taco was good - not perfect, but rock-solid - and I had a little tear in my eye when the guy at the counter rang up my bill. Most street food is cheap, from New York slices to Philly cheesesteaks. I just couldn't believe that something I had missed so much, something that spoke of home and comfort, could cost only $1.73.

Friday, 8:30 a.m., Mi Madre's
People can spend the better part of an afternoon debating the ideal ingredients in a breakfast taco - whole versus refried beans, corn versus flour tortillas, bacon versus chorizo, potatoes or no potatoes. Argue all you want, but give me this: Breakfast tacos are best with processed yellow cheese. That's right - I'm talking Velveeta.

If you grew up eating Tex-Mex, chances are you have a soft spot for Velveeta. (Chances are you have several soft spots, mostly around your midsection.) Breakfast tacos also frequently use Monterey Jack or cheddar; the former is too mild, while the latter melts messily, leaving pools of grease. When I open my tortilla at Mi Madre's, I find just what I want - bright orange cheese, the consistency of glue.

Friday, 9 a.m., El Chilito Tacos y Cafe
El Chilito is a taqueria gone to culinary school - there are oven-roasted tomatoes in the salsa and a distinct lack of flies swarming the kitchen. There's good cappuccino and, on a brisk morning, a Mexican blanket draped over the back of each patio chair. True foodies might sniff at such yuppie touches - though one of the owners of El Chilito (and El Chile Cafe y Cantina, down the block) earned his chef whites in the fine-dining kitchen of foodie favorite Jeffrey's - but they'd be missing out. When I unwrap the foil, steam ribbons into the air. I scribble in my notebook that the bacon is rich and salty. Later, I remember that "rich and salty" is the only way bacon comes. Look, I didn't go to culinary school. How can I say it? The breakfast taco was extra good.

Friday, noon, El Sol y la Luna
Originally, I had planned to eat breakfast tacos the way oenophiles test wine, which is by trying a bit and ditching the rest. So I ordered a chorizo migas taco at this South Congress spot and stood by the outside trash can. There was one problem: I couldn't stop eating. Grease leaked between my fingers and egg tumbled onto my chest as I hovered like a street person by the garbage, trying to shove the drippy mess into my mouth before someone took pity on me and tossed me a dollar.

Friday, 1 p.m., Polvo's Mexican Restaurant
In his definitive Tex-Mex Cookbook, Robb Walsh, a food critic for the Houston Press, calls refried beans "the mashed potatoes of Tex-Mex," not only because they're the quintessential side dish, but also because they're pumped full of salt and fat. If you go to this popular South Austin eatery - where there are always people on the patio sipping margaritas, even at 10 in the morning - try the refried beans. Get them in a taco. Get them on an enchilada plate. Get them on a napkin and suck happily.

Polvo's is my first stop on a ­breakfast-taco crawl down South First. There is also La Mexicana Bakery, across the street, a 24-hour spot known to inspire awe (and occasional sobriety) in the four a.m. crowd. And there's Little Mexico Restaurant, perfect for the authenticity snob who's looking for a restaurant that's gringo-free. The popular chain Taqueria Arandas sells three tacos for $2.29 (three!). At some point, I stopped being a writer and turned into a competitive eater.

Saturday, 10 a.m., Juan in a Million
It was in a tidy booth of this unfussy East Austin restaurant that I first fell for breakfast tacos. Juan in a Million's signature Don Juan-El Taco Grande is a triumph of taste as well as proportion - you have to order two extra tortillas to handle the spillage. Since that happy, gluttonous afternoon in 2000, Juan in a Million has won scads of awards from the Austin papers, including the title of Best Breakfast Taco from the college daily. But like a record-store clerk who brags about knowing R.E.M. before they went platinum, I like to say I loved the Don Juan taco first.

Sunday, 10 a.m., Joe's Bakery & Coffee Shop
How did I get this far without talking about tortillas?
Most of the previously mentioned restaurants buy their tortillas from a distributor and grill them with a little butter. They're still good, but not as good as tortillas made on-site - ask anyone who's been to Taco Cabana (still the best argument I know for fast food). Another place to taste-test at is this hopping bakery on East Seventh. You can finish off your breakfast taco with freshly baked cookies and cakes from the display case. As for me, my tortilla has put me in the mood for another tortilla.

Sunday, 11 a.m., Tacodeli
When you love something as much as I love breakfast tacos, you develop fierce, irrational prejudices. I once scolded a boyfriend for holding his taco wrong. My best friend's belief that the ultimate breakfast taco does not contain bacon usually receives my table-thumps of exasperation. And when someone recommended this place, which puts mashed potatoes in their breakfast tacos, I was prepared to throw down my napkin in horror. Let me tell you something: My ex still holds his taco wrong, and the ultimate breakfast taco does contain bacon, but mashed potatoes in my breakfast taco? Delicious.

Monday, 10 a.m., Tamale House
As much as some places advertise their breakfast tacos with banners and signs, the best spots are just as often hidden in some strip-mall dive between a laundromat and a Diamond Shamrock. I must have driven past the Tamale House on Airport Boulevard for five years before I realized people actually ate there. I didn't think it was a bad restaurant; I thought it was a condemned building. These days, the Tamale House has a sign boasting of the "fastest breakfast tacos" around, surely a virtue for those unenthused about having breakfast in a parking lot. Tamale House breakfast tacos are good, and cheap. But actually, it's their migas that are the best in town. Ahhh, migas. That's a whole other story.