Walking into El Gusano, Old Oakland's newest Mexican restaurant, is like teleporting south of the border. One minute you're on a gritty downtown street, the next you're in a tile-floored, hacienda-inspired vacation spot.

Fans circle lazily on the ceiling. Latin jazz pumps softly through the speakers, Mexican movies flicker on a wall above the bar, and the Virgin of Guadalupe gazes down from a colorful altar.

Owners Erin Brooks and Michael Sopher have transported many of the most successful elements of their popular San Francisco restaurant to their newest venture. Like Tropisueno, El Gusano is a casual taqueria by day and a full-service restaurant by night.

Callos a la Plancha is photographed at El Gusano on Thursday, March 28, 2013 in Oakland, Calif.  Seared Sea Scallops on served on a plantain chorizo hash
Callos a la Plancha is photographed at El Gusano on Thursday, March 28, 2013 in Oakland, Calif. Seared Sea Scallops on served on a plantain chorizo hash with an avacoda tomatillo salsa. (Aric Crabb/Staff) ( ARIC CRABB )

As you might expect from a place whose name translates to "the worm," El Gusano boasts a tempting array of tequila and mezcal-based cocktails. A Pepino ($9), for example, mixes Jimador blanco with fresh cucumber and a touch of Crème de Violette. Even the ubiquitous margarita is done beautifully here -- aji chili salt rims a nicely balanced blend of tequila, agave nectar and fresh lime on the most basic version ($8); other margarita options ($9) include a mango-serrano chile blend and a cucumber version with hibiscus-infused tequila.

Talk to anyone who's dined here, and they won't shut up about the chips and salsa. Normally, that's a fairly alarming thing to compliment. If you're praising the free chips and salsa, it does not bode well for the meal to follow. But I have to say, this colorful trio of salsas -- a zesty avocado-tomatillo, a flavorful tomato and roasted chile, and a zippy, Asian-inspired, Sriracha-based dip -- is extraordinary. The avocado-tomatillo puree really ought to come with a spoon. Or a straw.

Nearly everything that followed was equally impressive, from the charming service to the delicious, authentic, regional antojitos and entrees -- many of them recipes from the restaurant's chef, cooks and staff. The only problem with the menu is that there are far too many tempting possibilities to choose from, including some dishes you rarely see on Northern California menus.

We thoroughly enjoyed the Callos a la Plancha ($11) -- and it wasn't just that they were accompanied by that avocado-tomatillo salsa. The plump sea scallops were seared perfectly and served over an intriguing plantain-chorizo hash. No one flavor predominated; the small plate was a harmonious whole.

The scallops were one of five seafood starters. Other possibilities from the mariscos crudos and mariscos otras menu included a salmon crudo ($8), two ceviches ($8 and $11) and a garlicky sauteed shrimp dish ($10).

The Salbutes con Pollo ($9) -- chicken tinga, zesty pickled onions and a cabbage slaw atop thick masa rounds -- continued the small plates theme with a burst of vivid flavors and wonderful textures. We were unsure how to eat it -- forks didn't work well, and fingers were messy, but honestly, who cares when something tastes like that? The pickled onions and slaw rode the very edge of puckery, but I really like that.

Another antojito, Molotes de Elote y Barbacoa ($8) -- plump, cigar-shaped masa filled with barbacoa, corn and cotija -- was less successful. Those ingredients should have been splendid together, but there was a distinctly strange sweetness -- not a corn/masa sweetness, a wrong sweetness -- to the dish that made me think something had gone wrong in the kitchen.

It may have been a fluke, but I would not order the dish again, not when there are so many other tempting small plates, including Mexico City-style empanadas ($8) filled with pasilla chiles, mushrooms and cheese, beef cheek tacos ($8) and carnitas tostaditas ($7). And then there's the other half of the menu.

We were in a small plates mood, but the menu's flip side includes everything from enchiladas with nopales ($13) to pollo asado ($15), salmon slow-roasted in banana leaves ($17) and huaraches (three for $14) -- the dish, not the sandals. The thick tortillas are huarache-shaped, hence the name, and hold chile verde, carnitas and al pastor with pineapple.

We opted for the chile verde ($12) sans sandals. The comforting pork stew, cooked low and slow with tomatillos, peppers and herbs, was served with slightly sweet Mexican rice, soft fresh tortillas and beans. The dish was tasty, but a little more acidity to brighten the flavors could elevate it to something really special.

These are all authentic, regional dishes, made with care -- and with local ingredients, Niman Ranch beef in the tampiqueno ($15) and Petaluma free-range chicken in the asado. Even the Los Favoritos portion of the menu, which is devoted those classic old-school taco-enchilada combinations ($10.95 for two items, $12.95 for three), fills its tortillas with carne asada, barbacoa, pastor and tinga.

There's dessert, too, of course: A tres leches cake, flan, even a chocolate flan ($7 each). As I've mentioned before, I like to torture myself with flan. I agonize over it, knowing I will compare every bite to my Portuguese grandmother's absolutely perfect version -- or rather the idealized version that lingers in my memory. We're talking mythic flan, and I am always disappointed. So it's a compliment when I say, this was pretty good flan. A little firmer than my mythic flan -- served with a fork.

We'll definitely be back.

El Gusano

* * ½

FOOD: * * ½
AMBIENCE: * * ½
SERVICE: * * *
WHERE: 1015 Clay St., Oakland
CONTACT: 510-444-9676, http://el-gusano.com/
HOURS: Taqueria counter service 11:30 a.m. to 3 p.m. weekdays, dinner 5:30 to 9:30 p.m. Tuesdays through Saturdays
CUISINE: Mexican
PRICES: $-$$
VEGETARIAN: Several options, including Mexico City-style empanadas with pasilla chilies, mushrooms and cheese ($8) and enchiladas with vegetables, corn and cactus ($13).
BEVERAGES: Margaritas and other tequila-based cocktails
RESERVATIONS: Accepted through Open Table
NOISE LEVEL: Medium
PARKING: Some pay lots nearby, but the 12th Street BART station is a block away.
KIDS: No children's menu, but they will make baby burritos and quesadillas if you ask.
PLUSES: Flavorful, authentic Mexican fare served in charming surroundings. Terrific service.
MINUSES: Some dishes are outstanding, others are less so.
DATE OPENED: January.

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Ratings

Restaurants are rated on a scale of one to four, with four representing a truly extraordinary experience for that type of restaurant.

Price code

$ Most entrees under $10
$$ Most entrees under $20
$$$ Most entrees under $30
$$$$ Most entrees under $40