Since Mister Jiu's is, without question, the stalwart of the modern dining scene in San Francisco's Chinatown, it follows that the restaurant's sultry new upstairs bar would become the neighborhood's number-one destination for cocktailing overnight.

As expected, Moongate Lounge, which opened in Marchwith a lunar theme, seasonal drinks, and such creative dim sum as Jew's Chicken in a Space Suit, took off like a rocket.

Ready for your trip to the moon?(Trevor Felch)

Up some rickety wood stairs from the main restaurant, a dark door is marked only with a painting of a lunar eclipse, your first clue at the bar's thematic leaning. The design team, comprised of Jew's wife and business partner, Anna Lee, and Stephanie Wong of Swig Architects, took inspiration from moongates, those circular holes commonly found in the walls of traditional Chinese gardens and courtyards, and ran with it to the last delightful detail.

A large circular skylight crowns the lounge—a 5,000-square-foot banquet space dating back to the 1890s—with natural light during happy hour, and slowly fades towards darkness after sunset. Come nightfall, it's the half-moon bar, with its shelves of fine and rare spirits sparkling like stars, that serves as the guiding light in this moody, 55-seat den. Dramatically tall, crescent-shaped booths are upholstered in Chinese-red velvet; low-slung Midcentury-style couches are teamed with spare mini tables for a posh salon feel; and vibrant colors and accessories make the place pop: Nowhere else in town will you find such liberal use of turquoise, hot pink, and vibrant orange; pretty floral arrangements; geodes and crystals; and the "Smoking Man" painting by the bar. The mood is "spacey yet terrestrial" with a "mysticism vibe," says operations and beverage director Maz Naba, and perhaps has a bit of Palm Springs–groovy tossed in.

First and foremost a swanky bar, Moongate Lounge tapped Mister Jiu's mixology talent, Danny Louie and Alex Kulick (Kulick is now full-time behind the bar at Moongate), to craft six house cocktails, six seasonal ones, and two frozen drinks (frosé alert!).

The house cocktails, named for moons in the solar system, include Kerberos (gin, green Chartreuse, salted kiwi, celery, pink peppercorn) and the powerfully smoky and alluring Scotch-based Titan (Barolo Chinato, Lapsang Souchong tea, and toasted brown rice).

Among the spring cocktails, with names referring to the lunar calendar, you'll find Clear and Bright, a fresh and tangy, almost numbing delight of tequila, nasturtium, green Chartreuse, and a bracing black pepper syrup. Vernal Equinox adds jasmine and bitter melon to the bones of a martini; and Rain Water takes the characteristics of a piña colada and then adds jasmine and the color trip of blue algae to an ice-filled drink. The most out-there creation? The vodka-and-egg-white-based Start of Spring, with strong spring pea notes mixed with Suze, sesame, honey, and sarsaparilla.

Choose a low-slung sofa for communal imbibing or a high-backed velvet booth for more intimate rendezvous.(Daniel Triassi)

Of course, all these tempting cocktails won't stop revelers from ordering up lemon drops with Grey Goose vodka, but alas they don't carry Grey Goose—rather rare and exceptional spirits are poured here by the ounce for interested guests. Those pours add up with the buzz, however; look out for the A.H. Hirsch Reserve 16-Year Bourbon at $225 an ounce.

Prefer a glass of wine? The selection here comes courtesy of Louisa Smith, the same woman behind the strong wine program at Lord Stanley, and is generally of the organic and/or biodynamic persuasion. It seems the team that cares deeply about farming practices when it comes to the ingredients for their food applies the same philosophy to what they pour in your glass.

If you've come to Moongate to eat, you'll find plenty of stellar options as Jew takes the opportunity of the laid-back venue to experiment with clever riffs on regional Chinese cooking (Xinjiang lamb skewers); updated takes on Chinese-American dishes (Alaskan crab rangoon); elevated spins on dim sum favorites (pig trotter ham sui gok); and grazing snacks along the lines of salt-and-vinegar shrimp chips or smoked oyster youtiao (think beignets). There are a dozen or so dishes of all sizes to choose from, including a rotating special. Yes, you'll find that Chicken in a Space Suit: a boudin blanc–style sausage wrapped in a soft bao resembling the puffy suit of the Michelin man (Mister Jiu's has one Michelin star, by the way). And yes, it is basically pigs-in-a-blanket, executed by one of the city's most talented chefs.

Dishes include (from left) salt and pepper Monterey squid; pig trotter ham sui gok; and Chicken in a Space Suit. Pair with cocktails like the Start of Summer (left) or the Grain and Ear. (Daniel Triassi)

For dessert, look for coconut lychee cake and Parisian egg tarts by Melissa Chou, a leading Bay Area pastry chef who first soared to prominence at the much beloved but now-closed Aziza.

Design, food, drink—it all comes together in a wonderfully stylish yet thoughtful ode to history, quirkiness, and romance. And, as seems appropriate for a space that's been serving guests for over a century, Moongate Lounge has a timeless feel. Luckily, all it takes to get there is just one small step (or Lyft) for man.

// Moongate Lounge, 28 Waverly Pl. (Chinatown), moongatelounge.com

Moongate Lounge puts a modern spin on Chinese dining culture.(Daniel Triassi)