WHENEVER I’M WAITING for a table at Cactus—which is not infrequently, by restaurant reviewer standards—I know how the bumper in a pinball machine must feel. There in the tight little entryway of this Madison Park restaurant, the waiters and the “waiters” carom off one another, each obstacles in the other’s determined pursuit of that most elusive of objects at Cactus: a table.

Cactus 4220 E Madison, 324-4140 Mon-Thu 11:30-3, 5-10; Fri 11:30-3, 5-10:30; Sat 5-10:30; Sun 5-10 AE, DC, MC, V; full bar

This popularity isn’t new and therefore isn’t news; Cactus has, in its nine years of business as a purveyor of admirable Spanish, Southwestern, and Mexican food, earned its constant crowd. This surplus they’ve tried to address in any number of ways, from sidewalk tables, quite charming in summer, to pagers for diners who choose to stroll the neighborhood while waiting.

Now they’ve introduced the most efficient fix yet—more interior space. Two months ago they busted through the wall to the empty spot next door, effectively doubling their dining area. Anchoring the new room is a cozy “S” of a bar, around which are several tables for drinkers and/or diners. Zoom in for a close-up on that bar, and more likely than not you’ll see another new addition at Cactus: a blue margarita.

Now it’s a perfectly good margarita, as it turns out, made with blue curacao and Cuervo and plenty of lime and lemon. The waiter who brought it to our table was a rather giddy young gentleman who gesticulated wildly and appeared ready at any moment to burst into song. We asked what else was new on the menu and he exclaimed about the nachos ($7.95), which the kitchen has always produced on request but never before featured on its list. We ordered them and knew immediately why: These nachos were dry, slightly burnt, scant of cheese—for that matter, scant of toppings in general, with only scattered bits of chorizo providing interest.

As we picked our way disappointedly across the plate we shuddered at the possibility that in its remodel Cactus had fallen into the bad-nachos-blue-margaritas-and-goofy-waiters genus of Mexican restaurants.

Yikes! Time for a new review!

Now, in a way, Cactus has always been two restaurants, one a better-than-average Mexican joint with homemade tortilla chips and chile rellenos and sizzling fajitas, the other a sophisticated interpreter of Spanish and Southwest American cuisines. Would the tapas still be worth a trip across town?

The empanadas ($4.95) sure were: pockets of fine pastry filled with a bold chorizo, cilantro, and goat cheese mixture. Patatas bravas ($3.95) were gold potatoes topped with silken roasted garlic aioli. Torta de jaiba ($5.95), a pan-fried crab pancake with scallions and a vibrant salsa fresca, was drizzled with chipotle cream; the juxtaposition of the sweet, charry pancake with the searing chile spice and gentle creaminess of the two sauces was bewitching.

Black bean and shrimp tostadas ($5.95) were also enticing, their chile zing enhanced by the citrusy coleslaw beneath them. The only failure was the garlic shrimp ($6.95), which were tragically overcooked in a glorious garlicky bath of chiles, sherry, thyme, and lemon.

With this feast we munched through several baskets of Cactus’ terrific, just-greasy-enough homemade chips, both corn-golden and beet powder-red, liberally dipped into a pot of thick, mild homemade guacamole ($5.95). (Bravos are in order to the busers, by the way, who labor tirelessly to keep diners from suffering the two top indignities of Mexican dining: seeing the bottom of the chip basket and the water glass.)

One last order off the starter list, a salad of baby field greens and goat cheese fried in beer batter ($5.95), was unexpectedly wonderful, strewn with candied hazelnuts and served with a sprightly vinaigrette of roasted jalapenos and green apple. At once tart and sweet, creamy and satisfyingly crunchy, this simple masterpiece embodied Cactus at its best: innovative, fresh, and ablaze with recognizable yet somehow wholly new flavors.

Entr饳 were generally as solid, though at Cactus (as in so many restaurants) the lion’s share of the creativity and fun seem to reside on the starter side of the menu. The elements of the soft white corn tacos suaves ($9.95)—that is, the grilled chicken (or chorizo, or sirloin), the lettuce, the black beans, the Spanish rice—arrive strewn with roasted Spanish pumpkin seeds over homemade white corn tortillas. The Navajo taco ($8.95, $10.95 with chicken) is a similar setup, only with all the goodies—the delicious Anasazi beans, jack cheese, greens, tomatoes, onions, guac, sour cream, and pico de gallo—piled atop a Frisbee of sweet and puffy Indian fry bread. Sweeter than you were expecting, it’s also strangely addictive, compelling you to dive into your doggie bag—you will have a doggie bag—on your way home.

Chicken-fried chicken ($12.95), another monstrous dish, is spicy fried chicken, small-town down-home to its core, served over green chile-kissed mashed potatoes with zingy chorizo gravy and crowned with a splashy pico de gallo. This one’s a witty meeting of the Americas, what they might eat at a Mexican church potluck, done with a worldly surehandedness and a coy little wink.

Yucatan-style roasted pork ($9.95) arrives dramatically in banana leaves, fiery with the complex flavors of achiote and citrus and spices aplenty. Diners place moist chunks of the meat along with pickled red onions into corn tortillas to eat.

The flavor here is beautiful, deep and rich and bottomless. Such vivid flavor is Cactus’ calling card, but it can be overwhelming. One evening’s special, steak stuffed with Cabrales cheese ($13.95), seized us by the back of our palates from the first bite and never let go. The beef, sensitively cooked, arrived over tortilla, stuffed with slivered roasted vegetables, and drenched in a yowza! sauce of Tabasco red pepper vinaigrette with New Mexican red chiles. This vinegary sauce, combined with the intensity of the Cabrales cheese, rendered a nicely conceived dish a tyrant of flavor, much too relentless to finish.

Desserts were great, particularly an amazing triple milk flan ($4) and bananas with rum and ice cream ($4.95), and soothed our eyeballs back into their sockets. Licking our spoons, we concluded that the old Cactus, captivated with Spanish cuisines the world over, is still having lots of intelligent fun in the kitchen, and most often getting it altogether right. The other Cactus, worried perhaps about filling up its shiny new seats, is playing up the more Azteca-like aspects of its operation.

Which just means that now, more than ever, Cactus is literally for everyone. Great. On our last visit they were all ahead of us in line; even with the new room, we waited 20 minutes on a Wednesday night, bouncing as usual off the waiters.

Under the influence of a blue margarita, we discovered, this can be quite fun.