The first thing one notices when entering Leo's Oyster Bar (besides the massive palm fronds that unfurl across the pastel tropical wallpaper covering the restaurant's soaring atrium) is the glow.

Just one step inside from a somewhat gritty and quite dark nighttime stretch of Sacramento Street, the warmth of the lighting here, emanating a golden hue from bronzed seashell sconces and the onyx bar lit from underneath, is almost uncanny—and immediately enchanting, as though you just slipped into a whole bathtub bubbling with Champagne. I say as much to Anna Weinberg, the restaurant's well-known owner and hostess for the night, and she smiles back at me as if to say “Mission accomplished."

(You'll find none of the usual by-the-glass offerings when it comes to Champagne at Leo's. If you're after a single flute, Ruinart Blanc de Blanc, Gerard Bertrand Brut Rosé, and Laurent Perrier Ultra Brut are on offer. If it's a bottle you need, prepare to take your time in making selections, and possibly break out the big bucks.)

Things proceed as one might expect inside a Champagne bubble bath: There is a copious amount of Champagne to drink (including a lovely Ruinart Blanc de Blanc by the glass) as well as excellent cocktails (Don Draper might have enjoyed the Scotch- and amaro-based Office Supplies); indulgent little dollops of osetra caviar atop truffled beet blinis; and towers of raw delights and chilled seafood including immaculately shucked oysters (we love the briny St. Simones and the “Fancy" Hammerslys topped with pickled tomato and horseradish), king crab legs, and Maine lobster claws. If it all sounds very opulent, well, it is—but all is rendered with the grace of simply having gotten it right.

Thanks in part to Weinberg's trademark hospitality and to Ken Fulk's and Jon de le Cruz's intimate design—brass-trimmed caramel-hued wood clads the walls, black-and-white tiles cover the floor, ferns give life to the atrium, and dates cozy up side by side on the long banquette—there's nothing much of pretense here even despite the fact that, on our recent visit, celebrity chef Jonathan Waxman (Weinberg's mentor who is soon to open Brezza Emporio and Pizzeria in Ghirardelli Square) and Quince/Cotogna pastry chef Shawn Gawle happen to be dining, separately, at the bar. There are other vaguely familiar faces too, the kind that have likely graced the local social registers; but all seem more intent to see the ceremony of cutting open the papillote that envelopes a dish of steaming mussels—aromatic with pancetta, olive, tomato, and chili—than to see the reflections of their fellow diners in Leo's many mirrors.

(Anna Weinberg once told 7x7 that "Anything can happen on toast." At Leo's, sea urchin with ginger, soy and scallion happens on triangles of brioche.)

As at Leo's sister restaurants (The Cavalier, Marlowe, and Park Tavern), Chef/partner Jennifer Puccio's menu tempts us with so many coquettish small pleasures (perfect for date nights) that ordering an entrée doesn't always seem entirely necessary. The tiny tempters begin with a selection of hot oysters—the wing fried oyster perched atop a deviled egg, a signature in all of Puccio's kitchens, is a tasty given; and move on to more caviar bites, including salmon roe and smoked salmon on an everything chip; small plates (a housemade tater tot with brandade; a crab and lobster cake with cucumber); and toasts—another Big Night Restaurant Group obsession—laden with everything from tuna conserva to sea urchin; and crudos (Japanese hamachi with charred avocado; diver scallop with jalapeño and lime).

(If it isn't already, the New England lobster roll, served with fries and an umami bomb of "dynamite sauce," is soon to become Leo's signature.)

There are also clam chowder and lobster bisque, and a trio of Louie salads waiting to be paired with gin martinis and pickled veg by the FiDi's well-heeled lunch crowd (look for midday meals to begin later this spring). If you've saved room for an entrée, we recommend the aforementioned mussels. But what you'll really want is the New England lobster roll with uni butter and crispy fries: Leo's answer to Marlowe's burger and the Cavalier's fish and chips, this is the dish that you'll crave until next time.

Friends of co-owner couple Weinberg and James Nicholas, as well as regulars to their restaurants, have come to expect an elevated way of doing things. Their menus can't be replicated, their service not easily matched, and their spaces…let's just say that, outside of Fulk's Battery, they achieve a level of fantasy untouched by other San Francisco social spaces. But that being said, even Leo's feels special among its family of businesses. There's something more here. Something prettier, more elegant, more romantic. A throwback to a more glamorous era when dinner and drinks was a celebration.

(Like Leo's cocktails—many of which rely on lighter spirits and fresh herbs—the desserts here feel fresh. We're still thinking about the roasted pineapple ice cream sundae with coconut and pistachios.)

Perhaps because it is tended with a love inspired by its namesake, Anna and James' cherubic son. Or perhaps it is just in the many carefully chosen details, such as the delicate, handpicked vintage vessels that make Emily Lucchetti's desserts even sweeter. Or perhaps I'm just a writer with a particular taste for a luxurious space in which to dress up and slurp Champagne and oysters next to pretty people. Whatever it is, one thing is certain: San Francisco has its new special occasion destination. Just wait till they open the exclusive Champagne room, to be dressed in gold leather, rattan, and even more fabulous wallpaper come March. Intoxicating, non? // Leo's Oyster Bar, 586 Sacramento St. (FiDi), leossf.com

(Never underestimate the power of wallpaper! Just two days before Leo's was scheduled to open, Weinberg had a revelation: the paper that was to cover a back hallway absolutely had to be hung in the entryway. The result is a spectacularly feminine and tropical space, hung with glittering mirrors and ferns.)