When I first started visiting Taqueria La Oaxaqueña back in early spring, it was newly opened and as yet untapped by the local Mexican community. I could mosey in at 12:30 p.m., slide into one of the booths lining the modest room's walls, and be stuffing my face with a sultry, sloppy tlayuda in eight minutes flat.Not anymore. The only available table left during my most recent excursion is small and wobbly, and stuck right in the middle of the floor. Workers have jammed into the booths for their lunch break, talking animatedly as they clasp their tortas (generously stuffed Mexican sandwiches). The owner, Rosalia Ruiz, has continually added small, thoughtful touches to the place: gauzy, floral curtains to filter the summer sun; red T-shirts embossed with the restaurant's name for the two fast moving servers. I swallow my booth envy and take the wobbly table. I want my tlayuda. A glorious street food from Mexico's southern state of Oaxaca, the tlayuda (pronounced klie-YOU'-da) has quickly made it to my short list of culinary addictions this year. It's part pizza, part Taco Bell concoction with pedigree: An oversized tortilla, bigger than the average dinner plate, is griddled and smeared with bean paste, then topped with pork or steak, lettuce, two kinds of cheese and sundry other goodies. Each bite is different, each mouthful a riot of crispy, salty, mellow, meaty and spicy, all vying for your taste buds' attention at once. That the whole mess gets all over your hands and smiling mug as you plow through it just makes it that much more satisfying. Several restaurants on the outskirts of the metro area now offer tlayudas, but Taqueria La Oaxaqueña serves my favorite. Ruiz has mastered the proportions of toppings. The tortilla is cooked firm but still pliant, and the spread of pureed pinto beans is just thick enough to provide a satiny foundation without becoming heavy. My preferred choice of meat is cecina, tender bits of pork simmered in a spunky red sauce. And I love the contrast of the two cheeses: the sharp bite of the feta-like queso anejo mixed with the languid, milky strands of quesillo, Oaxacan string cheese. But what seals the deal here is the salsa bar. Sitting in bowls, each adorned with ladles marked "Thousand Island," are three wondrous salsas -- smoky red, biting green, and guacamole -- to be poured liberally over your tlayuda (or anything else you order here). I was initially put off by the restaurant's guacamole. It's thin with no chunks. But I've since come to appreciate how effectively its glossy consistency melds with the other ingredients. My plan of attack when I dine at Taqueria La Oaxaqueña is to order a tlayuda, and then one additional something or other. Maybe a robust taco filled with tangy goat meat and a fluffy tuft of cilantro. Or perhaps a chicken leg and thigh smothered in Ruiz's suave, slightly sweet brown mole. During my last trip, I spot a blurb on the menu that says, "Remember we make homemade tortillas and tamales." I've tried the toasty fresh tortillas many times, but I'd never sampled the tamales. Tucked inside crinkly cornhusks, the masa dough is doused with either red or green salsa and steamed to a crumbly yet moist texture. Memorable indeed. But don't get too sidetracked into other diversions. Nothing you'll find on the menu will outshine the messy, marvelous tlayuda.