You can smell sizzling butter around Brennan’s dining rooms as waiters flambé desserts from wheeled carts.

Stroll around and you can hear the din of shoulder-to-shoulder conversation hovering over the bar and drifting down from parties upstairs.

You can see Royal Street foot traffic streaming past the windows that now line the front room, and you can watch as people stop and peer in at the courtyard and its soft vista of palms, brick and table umbrellas set far back.

And maybe, between it all, you can discern something in tune with the convergence of tradition, change and renewal so evident around New Orleans these days.

It’s on chef Slade Rushing’s menu, where egg yolk carpaccio is artfully rendered as a rich, pliant sheen to swirl over char-marked shrimp and fine sweet potato “hay,” and where crab remoulade is fattened with avocado between white disks of jicama shaved thin as a veil. At another restaurant, to follow these with an old-fashioned baked apple set in créme fraiche might feel incongruous. But here, it feels like an anchor back to the old Brennan’s and to the legacy that lets this huge, beautiful, improbably new-yet-historic restaurant make sense.

Brennan’s today is what an old New Orleans restaurant might be like if it evolved with the times while still balancing pride of place, Creole distinction and the showmanship of deluxe dining.

If that sounds like Commander’s Palace, well, it’s no coincidence. Co-proprietor Ralph Brennan is a protégé of his aunt Ella Brennan. She was a driving force of Brennan’s on Royal Street before the famous family rift in the early 1970s, and she went on create the modern Commander’s Palace. It’s easy to see this new Brennan’s as the restaurant the old Brennan’s would have gradually become had that family split never occurred.

But the changes here did not happen gradually. They came rapidly, and dramatically. They were sparked by a bankruptcy that led to a change of ownership. The huge undertaking has been guided by Ralph Brennan’s high-functioning restaurant group. And it’s been fueled by the staggering sum poured into the project, estimated somewhere north of $20 million, by Brennan’s co-proprietor here, Terry White, a local businessman with a yen for old New Orleans restaurants.

In the kitchen, the mandate was to reintroduce Brennan’s to a new generation, without discounting its trove of tradition and its Creole context. Rushing worked closely with Haley Bittermann, corporate executive chef for the Ralph Brennan group, on the culinary direction. The result is fine dining drawn to the grand old scale, following the template of its predecessor with its unusual focus on boozy “breakfast,” though now finished with a hand attuned to modern tastes and expectations at the table.

That doesn’t exclude the baked apple at breakfast, nor a host of dishes revamped from the old Brennan’s. Sauces gleam and taste just as bright. The English muffins girding the essential eggs Hussarde are toasty and chewy and laced with crisp as they deliver a mouthful of umami from marchand de vin sauce and salty, coffee-cured bacon. Eggs Cardinal looks like another poached egg standby but gives a more current cut to it with a crunchy base of fried boudin made from shrimp and lobster.

Brennan’s is the birthplace of bananas Foster, though crepes Fitzgerald is the better dessert and just as fun to see prepared tableside, provided you can abide firsthand evidence of just how much sugar is cooked into it. The crème brûlée is the best in recent memory, for once an example where getting at the rich custard is as fulfilling as tapping through the bubbly crust.

Milk punches (in several types) abound at breakfast. The wine cellar, a two-story complex larger than some bistros, is clearly courting awards, with particularly deep catalogues of Burgundy and Champagne.

The dinner menu is more contemporary than breakfast, and more open to change. For the filet Stanley, an idiosyncratic specialty of the old Brennan’s, the sliced bananas that once framed the steak are now integrated into the horseradish sauce, a creamy-sharp blend that works because together those ingredients taste more restrained than they would separately.

Two of this menu’s powerhouse dishes came to Brennan’s already in Rushing’s pocket from his own earlier restaurants — the sweetbreads and the BBQ lobster. The first gives Southern warmth and pork jus succulence to pan-roasted nuggets of sweetbreads over truffled grits. The second transforms the idea of lobster in drawn butter into a deeply flavored Creole crossover, akin to BBQ shrimp and just as magnetic for crusty bread or just about anything else you might drag through its tawny pool.

These more unusual, original dishes at dinner prove most rewarding. The Gulf fish — mahi mahi when I tried it — was reserved to the point of being plain. The turtle soup and seafood gumbo are both traditional, and neither stand out from renditions you’ve had elsewhere.

The biggest chance for disappointment, though, is likely for those who may still arrive anticipating the old Brennan’s, and for reasons that go beyond the menu and design changes. People count, personalities are a big part of a family-run restaurant, and the branch of the family that ran Brennan’s for a generation are no longer here. In fact, they plan to open their own restaurant, Ted Brennan’s on Decatur, with their longtime chef Lazone Randolph and in a style they say will be much closer to the old Brennan’s. Construction delays have mounted, though they expect to open in 2016.

The new Brennan’s on Royal opened just over a year ago, which at the current pace of the modern restaurant scene may feel like a lifetime. But for this one, it’s been an important interval for settling into its role and progressing through the particular New Orleans seasons.

That started with last year’s Carnival, with club luncheons in the upper rooms and plenty of people dropping in to get a drink and have a look at the place. In the spring, without football to interfere with leisurely weekends, it was the full-on “breakfast at Brennan’s” experience extending into the afternoon and paving the way to a Sunday wander through the French Quarter. In summer, it was the slower, more locals-dependent pace and a dining room filled with familiar faces. And now, back into the festive season that quickly sweeps from Christmas to Carnival, it’s the way the courtyard and newly designed bar feel as apt a gathering point for friends at happy hour as your favorite old hotel lounge.

Breakfast at Brennan’s naturally had to be part of this restaurant. But happy hour at Brennan’s? That’s a new concept, and the way the bar fills up shows how the rethinking that went into this landmark has reintroduced it to people and given them new ways to access it. It feels new, it feels familiar, it feels right.

Follow Ian McNulty on Twitter @IanMcNultyNOLA.