Hai Hai, the delightful newcomer from the talented couple behind the similarly delightful Hola Arepa, is one of those charmed restaurants where nearly every one of its well-engineered components fosters a single emotion: happiness.

The vivacious, travelogue-esque food and drink. The camaraderie that blossoms out of the menu's emphasis on shareability. The service staff's all-in attitude. The tropics-in-the-Twin Cities setting. The easygoing prices.

The couple's follow-up to their Latin-flavored Hola Arepa focuses on a different corner of the globe. Christina Nguyen is of Vietnamese descent, and she and her husband, Birk Grudem, are channeling that rich cultural and culinary heritage — as well as tapping their extended travels through Southeast Asia — into their exciting new venture.

What's admirable about Nguyen's cooking is that she's skipping the whole Greatest Hits compilation.

"I disappoint people every day because I don't have pho, or bánh mì," she said. "But there are so many other restaurants that do all of that so well. At Hai Hai, we're trying to go toward ingredients, and dishes, that people can't find anywhere else."

Which explains the presence of water fern cakes, small ramekins filled with steamed rice, ground pork, mung beans, crisped-up fried shallots and sweat-inducing Thai chiles, a combination that's best described as an open-faced dumpling. Nguyen grew up eating a version of the dish, but experienced it in a new way when the couple were exploring the historic Vietnamese city of Hôi An, and the experience struck a chord.

A firsthand encounter of a much-copied, pomp-and-circumstance dish called cha ca al Vong — in the equally famous Hanoi restaurant of the same name — inspired another Hai Hai wowser. Nguyen extrapolated its principal elements (turmeric, dill, shrimp paste, fish sauce), incorporated flaky, snow-white, pan-fried cod (a favorite of hers) into the formula and added rice noodles. The results are spectacular.

The polyglot menu takes excursions away from Vietnam, culling memories of extended vacations the couple have enjoyed in Thailand and Bali. A standout is when Nguyen mimics a Balinese suckling pig delicacy. Instead of pork, she uses chicken thighs, marinating them in a full-bodied blend of Balinese aromatics (turmeric, lemongrass, coconut, lime leaves, chiles) for a day, then using the grill to forge a delectable contrast: juicy, tender meat and crackling skin. It's currently my favorite way to spend $14.

Hai Hai's unapologetically bold approach to vegan and gluten-free fare — and their crossover appeal to those not following those diets — is a role model for restaurants everywhere. Ditto the attention to detail, from the purity and vivaciousness of the nuoc cham sauce to the garden-fresh herb pile-on that enhances nearly every dish, an effort that requires Nguyen to routinely make manic shopping trips through a half-dozen metro area markets.

One particularly memorable blend — a mix of musky Rau Ram (Vietnamese coriander), purple and earthy Tiá Tô, mint, cilantro and Thai basil — improves several dishes, including tender clams redolent of lime and garlic. Its crowning example is a slender beef sausage that sings with ginger, shallots, lemongrass and fish sauce ("just all the good things," said Nguyen with a laugh), then wrapped, sausage casing-style in a betel leaf, grilled and made the centerpiece of a wonderfully messy lettuce wrap. It's not to be missed.

Another one of the menu's many admirable traits is its approach to salads, filling each one with a rainbow of colors and textures: a toss of purple cabbage, tart banana blossoms, crunchy peanuts, snappy shrimp and brightly acidic grapefruit (a shout-out to a lunch that revived Nguyen on a sweltering Vietnamese beach), or spaghetti-like strips of green papaya, their refreshing coolness in vivid contrast to the fiery combination of garlic and Thai chiles. Oh, and don't miss the life-affirming approach to two rices — one is puffed, the other smeared with curry paste and fried until it's crispy — both blended with cucumbers, onions, ginger and a blazing chile finish.

Nguyen gleefully transforms a guilty pleasure, fried cream-cheese wontons, by incorporating a key bánh mi component, chicken liver pâté, then punching up the sweet-and-sour finish with a chile-fueled passion fruit sauce. Weekend brunch is another adventure, in part because the kitchen stretches far beyond brunch-ifying its dinner dishes with the old add-an-egg trick, and Grudem's contributions behind the bar are a ton of fun.

He's made the bar a destination all its own, partly by imaginatively incorporating the kitchen's ingredients vocabulary (turmeric, lemongrass, lime leaf, Thai chiles) into a long list of well-conceived libations. One of his more genius moves was embracing the sugar cane press, a showy gadget that's the basis of some of the most refreshing cocktails — both boozy and nonalcoholic — that I've encountered in ages.

By reviving an eyesore of a boarded-up building (its most recent tenant, a skeezy strip joint, exited a few years ago), Nguyen and Grudem are proving themselves to be one of the city's most effective urban renewal forces; they accomplished a similar feat when they transformed a utilitarian former convenience store into the people-magnet that is Hola Arepa. Perhaps they could be persuaded to take on the Lake Street Kmart?

The 114-year-old structure's battered tile and wood floors burnish all kinds of time-stamped patina into the proceedings, and the investment in enormous windows pays off big-time as the outside world is drawn in, and vice versa.

The long, narrow interior spaces are softened by a Bachman's-like level of greenery (the sound level is more animated than loud), and the couple's amiable do-it-yourself decor boasts an enviable eye for amusingly patterned wallpapers. Oh, and they've crafted a patio that's destined to become a warm-weather headquarters for a fairly wide segment of the dining-out demographic.

Pastry chef Ericka Trinh's output impresses. She ingeniously infuses a luscious pot de crème with a pair of coffees, one with bitter chicory undercurrents, the other with chocolate notes. A playful parfait layers all kinds of goodies (vegan gelatins, lychee, pink tapioca soaked in coconut milk and crunchy, puffed-up basil seeds) into a giddy whirl of textures and comic book colors, a cool, smile-inducing repast for kids of all ages.

Her masterpiece is a marvel of restraint: a housemade tofu — its silky texture indulging in some major panna cotta cosplay — that floats in a delicate ginger-lemongrass syrup, a surprisingly light, not-too-sweet and wholly welcome way to finish a meal.

If there's a roadblock to Hai Hai-induced bliss, it's the restaurant's consumer-unfriendly approach to reservations. Sure, parties of six to 12 can secure a table (on certain nights, and only via Hai Hai's website), but the vast majority of diners will run the risk of playing — and playing, and playing — the waiting game at the front door. At this wildly (and justifiably) popular restaurant, that's an uncharacteristic bummer.

Hai Hai
Rating: ★★★½ out of 4 stars
Info: 2121 University Av. NE., Mpls., 612-223-8640, haihaimpls.com
Hours: Dinner served 3-10 p.m. Tue.-Sun., brunch served 10 a.m.-
3 p.m. Sat.-Sun. Bar open to midnight, with limited food menu served to 11:30 p.m.
Service: Knowledgeable, attentive and fun-loving.
Price ranges: With few exceptions, a $10-and-under menu.
Recommended dishes: At dinner, water fern cakes, fried wontons, banana blossom salad, green papaya salad, crispy rice salad, chicken thighs, turmeric and dill fish, beef grilled in betel leaf, Vietnamese che, silken tofu. At brunch, caramelized pork congee, khao soi noodle soup, laksa shrimp and grits.
Beverage program: A superb list of imaginative and offbeat cocktails ($9), basic (and competitively priced) beer and wine options.
Special menus: An admirable amount of attention paid to those who follow vegetarian, vegan and gluten-free diets.