When one of St. Paul's oldest and most beloved restaurants reopened with a bang in February (it had been dormant since mid-2013), the city's dining equilibrium seemed to have steadied itself.

No wonder. The Lexington, housed for 82 years in a forbidding brick fortress at the key intersection of Lexington and Grand, embodies a considerable chunk of the saintly city's social psyche, its wood-paneled rooms long acting as a private country club that's open to the public.

Good news, all, but it's nothing compared with having chef Jack Riebel back in a kitchen, where he belongs.

The project is a homecoming for Riebel. Although a St. Paulite to the core (he grew up three blocks from the Lex, and trained at what is now St. Paul College), he has spent the bulk of his long and influential career primarily in Minneapolis, where he sharpened his considerable skills at Goodfellow's and the Dakota Jazz Club & Restaurant, along with a stint at the Stillwater iteration of La Belle Vie, before wowing diners with his wholly original Butcher & the Boar.

After that blockbuster success, he started talking about his next step.

"A supper club," Riebel recalled. "A modern one. Supper club food isn't bad; it's just dated."

That was five years ago. It took a new partnership — Josh Thoma and Kevin Fitzgerald, both with St. Paul roots and co-owners of the wildly popular Smack Shack in Minneapolis' North Loop — to transform Riebel's dream into a reality. At the Lex, no less, the sanctum sanctorum of Twin Cities supper clubs.

"What is a supper club?" Riebel said. "It's a communal gathering place that feels special but is very approachable, with Midwestern cooking that everyone can immediately understand. My challenge with the Lex is, how do I take this institution and make it feel modern, without losing the history of it, the lineage of it? It's the most difficult task that I've taken on."

Making the old new

Riebel's most memorable dishes deliver an idealized flavor of nostalgia, suggesting the most cherished qualities of the past without relying upon rote replication, or kitsch; it's definitely a strategy of improvement through modernization.

For years, those in the know at the Lex could order liver and onions, an off-the-menu staple. Like his superb, gotta-order chicken pot pie (oh, that buttery, dimpled crust), Riebel pays homage to that tradition by making it infinitely better.

At its center is an enormous slab of velvety, pan-seared foie gras, an exercise in sumptuousness that's appropriately finished with three highly imaginative approaches to onions and a sweet-smoky bacon brittle.

Rather than a standard shrimp cocktail, Riebel channels the memory of a long ago beach vacation on the Yucatán Peninsula, marinating octopus and shrimp in lime juice, olive oil and chiles for a wonderfully light-and-bright starter. As for the saltines, "They keep it workmanlike," Riebel said. "Nothing too fancy."

Memories of North Shore trips of his youth led to another wowzer, a platter with deliciously different approaches to smoked freshwater fish: creamy salmon-sour cream rillettes, a whitefish riff on bagels and cream cheese (with snappy pumpernickel toasts) and delicate trout that's cured and hot smoked. Like all of the menu's appetizers, it's designed to be shared. Not ordering it is unimaginable.

Ditto the onion rings, made with wide ribbons of firm, white onions fried in an old-school flour/cornstarch batter until the coating — thin and delicately, delectably crispy — holds its shape. Wow.

Less shareable but no less impressive are the soups, starting with a sublime purée of caramelized onions (with mellow hints of sherry) garnished with a giant crouton crowned with an onion confit, tons of Wisconsin-made Gouda and pops of black truffle.

A wood-burning grill insinuates the flavors of Minnesota hardwoods into a variety of dishes, primarily oysters (so good) and a handful of skillfully rendered steaks. But jumbo crab legs — split and brushed with butter blended with house-made Sriracha — also blossom on the grill's heat. So does a heaping platter of spare ribs, which get their start in the oven before their honey-soy-chile glaze (the kitchen's nod to the supper club universe's tiki subset) gets a cracklingly good finish on the grill.

Hefty portions, Parker House rolls

Sure, the Lex has its flaws. Some of the menu's remade classics get their due, and then some — witness a flawless steak Diane, or a salmon Oscar so tasty, right down to its supple béarnaise sauce, that it makes a person wonder why it ever went out of fashion. But others don't just gently nudge supper club boundaries, they redefine them, and not to their benefit. One example: A chile-fueled plate of lobster-tossed spaghetti was blazingly, unrealistically spicy.

Despite the skill on exhibit here (let alone the long list of flawlessly prepared side dishes), does the local dining scene really need another steakhouse-like enterprise, particularly in this era of ever escalating beef prices?

And, let's face it, even when taking the lower-priced bar menu into account, the Lex is more expensive — making it less accessible — than its predecessors. That's not to say that value doesn't play a role, because one time-honored supper club convention that's followed to a T is a tendency toward hefty portions.

"We send a large number of doggy bags home," Riebel said with a laugh.

Pastry chef Louisa Farhat follows her boss' lead with uncomplicated, well-rendered classics. She's also responsible for the soft, garlic-scented Parker House rolls that arrive with every meal. The kitchen turns out 500 of them a day, and their grandmotherly goodness stands in marked contrast to the artisan sourdoughs and crackers that populate most contemporary bread baskets.

True to its past

In restoring the Lex's faded luster, ESG Architecture & Design of Minneapolis stayed fairly true to the building's storied past.

Yes, the extensive millwork — enough to outfit a smallish courthouse — is still there, painstakingly refurbished and radiating Old World charm like nobody's business. The kitchen, long hidden, now sparkles behind a wide bank of glass in the rear dining room.

True, the forbidding exterior has retained its windowless, mausoleum-like aura. But the once-empty second floor will soon come to life with private event spaces, and a 40-seat rooftop patio and bar will add a demographic-broadening jolt of informality.

Most of the transformation is invisible to diners' eyes. After purchasing the property in 2014, the ownership trio learned that their new toy was a deferred-maintenance wreck. Gaining countless 21st-century necessities required an investment in excess of $5.5 million, a figure equivalent to the Lex's bar selling nearly 460,000 of its refreshing $12 Singapore Slings. That's a significant pile of cash, and a major show of faith in this beloved institution.

It's also a gamble, betting on the kind of white-tablecloth dining style that's waning as diners lean toward more casual experiences. But with Riebel at the helm, the Lex deserves a successful future.