Restaurants will save downtown Miami. Despite the efforts of the city, its boosters, and the unclear intentions of real-estate developers, whenever one talks about the blocks surrounding historic Flagler Street, it's mostly the restaurants they speak of. Recent years have brought a flurry of talent to an area that to this day is almost devoid of life when business hours give way to nighttime.

But a closer look reveals signs of activity. A few hungry souls chomp away at the smoked fried chicken inside Sparky's Roadside Barbecue. Nearby, crowds pile into Alloy Bistro Gourmet and Deme Lomas and Karina Iglesias' Arson and Niu Kitchen for some of the city's most exciting Spanish-tinged fare. On many corners, a swell of new bars with well-made and reasonably priced cocktails are keeping people in the neighborhood or drawing them back at night.

Pez (20 W. Flagler St., Miami; 305-570-3440; pezmiami.com), from Mexican culinary sweetheart Javier Plascencia, opened in early December just steps from the county's historic and dilapidated courthouse. Inside, the restaurant shows all the vestiges of hipster dining. Exposed brick lines one wall of the space, and Edison bulbs dangle from a high unfinished ceiling. The centerpiece of the 140-seater is the bar, which boasts an impressive collection of smoky mezcals, as well as a glassed-in wine room with a hard-to-find array of Mexican vintages.

The place, however, falls short of the standards set by its colleagues in the neighborhood and by the growing of collection of Mexican eateries across the city.

Photo by Adriana Fernandez

Mexican cuisine is highly varied, with preparations and ingredients that shift as you move from north to south and east to west, but the tortilla remains constant. Recent years have brought an influx of better tortillas to Miami, mostly thanks to Taquiza's Steve Santana, who some years ago lined up shoulder-to-shoulder with great chefs from across the nation as they began importing heirloom Mexican corn and turning it into masa through the fickle process of nixtamalization.

Pez's tortillas wither in comparison. Chef de cuisine Miguel Angelo Gomez, who is 25 and came to Miami after spending three years at Plascencia's other restaurants in Tijuana, says they're made by a small supplier. Yet the crisped corn rounds that hit the table as bread service and are the foundation of tostadas that taste like they were pulled from a movie theater concession stand. The whiter, soft corn variety that forms the restaurant's tacos has the rubbery texture and cardboard-like aroma of cheap supermarket tortillas.

Of the former category, it's the vegetarian tostada called ceviche de lentejas ($9) that fares best. A toothsome combination of green lentils and barley is tossed in sesame oil and Banyuls vinegar, which lends acidity with touches of sherry and balsamic. An underlying slick of almost raw black bean purée adds some rich heft, while a scattering of watercress creates a rounding smack of peppery spice. The atún con machaca ($13) uses large cubes of scarlet tuna tossed with pico de gallo, ponzu sauce, and sesame seeds. It's then topped with Oaxaca chili, habanero cream, avocado, and the fluffy dried and shredded beef called machaca. Tossed together with the tuna, it turns into a kind of savory, salty jerky.

Photo by Adriana Fernandez

If the machaca's texture is too unpleasant, which it is on a trio of grilled oysters daubed with ponzu butter ($10), it will require a keen eye to keep it out of the rest of the meal. The ingredient, which is imported from Sonora — Baja and Tijuana's easterly neighbor — appears with a similar smoked tuna preparation that forces its assertive, sometimes oily flavor onto a handful of dishes.

That theme of identical flavors and ingredients is one that winds its way through the menu. Most of the tacos are crowned with too many toppings that mask the flavor of limp beer-battered fish ($5) and beer-battered shrimp ($6) and even muddle the Gobernador ($6), with Maggi sauce-marinated shrimp seared in epazote butter. The standout is the Tijuanero ($7), with an unencumbered mix of carne asada, tender octopus, and buttery shrimp.

In a similar vein, the tlayuda ($28) smartly combines a whirlwind of ingredients on a foot-wide masa crisp that creates a pleasant, highly sharable (at the table and on social media) moment. Atop a smear of refried black beans comes a layer of house-cured Ocean Blue kanpachi (farmed off the coast of Baja and also the current foundation of the restaurant's crudo) with creamy lobes of sea urchin, a piquant avocado vinaigrette, and perky watercress. Get them all into the same bite and it's enchantingly sweet, spicy, and savory with a delicate oceanic underpinning.

Photo by Adriana Fernandez

That same light touch can be found in Pez's chile relleno de marlin ($18), in which a tender roasted poblano is filled with that smoked tuna and surrounded by a sauce made with tomatoes, tomatillos, and guajillo and ancho chilies — the last adding another hefty dose of smoke. If the accompanying tortillas were better, this dish no doubt would be a signature. A fat, beautifully cooked loin of halibut is served with a toasty hoja santa leaf ($25), and the two make the perfect match, with the fish's delicate, fleshy sweetness highlighted by the herby greenery of an indispensable ingredient in Mexican and Central American cookery.

Everything else on the menu at Pez should be on par with that dish. Most suffer a level of repetitiveness in ingredients and flavor that is bewildering to see from a chef with Plascencia's curriculum vitae. Perhaps it's the distance from his home base a few thousands miles away or a lack of understanding the great strides that have been made in Miami Mexican cuisine thanks to chefs such as Taquiza's Santana and Cantina La Veinte's Santiago Gomez.

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