Secret bar food specials that you can only access with UV light. Getting sprayed with an atomiser while eating spanner crab rice balls topped with blue caviar. Seriously good cocktails. Wagyu beef spring rolls laden with shaved truffles. We're not in Marrickville any more, Auntie.

In fact, the new Hello Auntie has come a long way from the inner-west Vietnamese restaurant established in 2015 by Cuong Nguyen.

It's the liveliest of all the new offerings at Darling Square, with its tables spilling out into the square from a dimly lit, monochromatic dining room, and a bottle-lined cocktail bar.

Behind the bar, Roy Subhanker (Chin Chin) swizzles up a damn fine negroni-based cocktail ($18), adding to the Campari, gin and Antica Formula vermouth trifecta, velvety d'Usse cognac part-owned by rapper Jay-Z.

That atomiser? It comes with a perfectly round, deep-fried ball of spanner crab rice ($17) topped with tangy finger lime and luxurious scampi caviar. To enhance the eating experience, staff spray you with citrusy yuzu. It's silly, but refreshing.

The menu is not so much balanced as a series of pot shots at a common goal: bringing us up to date with how young Vietnamese Australians like to eat.

Flora, one of the lively, engaged floor team, says she grew up in Sydney eating Vietnamese food – and everything else as well. "This is just how we like to eat," she says.

So what do you get when Vietnamese food comes with multiple influences, via a chef who has cooked French, Italian and Japanese food?

You get egg noodles with minced wagyu studded with peas and deeply flavoured with tomato, miso, fish sauce and basil under a dust storm of grated grana padano ($20). It's basically Vietnamesed spag bol, and bloody delicious it is, too, the soft, thin noodles carrying a rich, deep sauce jam-packed with umami.

Today's spring roll special is filled with shredded wagyu, ($8) and roofed with tiles of freshly shaven truffle, which seems gratuitous.

Duck and porcini gyoza ($22) are more like floppy agnolotti with a soft, gentle filling, swimming in a pond of rich, velvety demi-glace with rounds of watermelon radish. Sometimes I wish this food would make up its mind which side it's on – East or West.

Not everything is new-school, and I can recommend the traditional,turmeric-golden banh xeo pancake filled with onions, bean sprouts and crunchy jicama ($16), to which you can add duck, chicken, prawn, pork or tofu for a little extra. It's so crisp it causes quite the cacophony when they cut it with scissors into manageable bits.

There's no dessert menu because there's only one dessert. Part Eton Mess, part pavlova, and part trifle, it's a pleasant, crowd-pleasing, crunch-and-cream mash-up that combines raspberry jelly, double cream, pistachio butter, crisp meringue shards and strawberries macerated in yuzu and white soy ($15).

Things are quieter at lunch; the big drawcard being Auntie's take on pho dac biet, Pho DSQ ($19), made by Cuong's mum, Lynda. Instead of the usual stringy "car wash" bible tripe she uses the far more enjoyable honeycomb tripe, and replaces beef balls with a slab of soft wagyu meatloaf.

Along with the usual brisket, raw beef, tendons, satiny rice noodles and deeply favoured beef broth, it's mighty. And that's without being showered with truffles, or sprayed with yuzu. Go figure.

The low-down

Vegetarian: Five dishes on regular menu, plus specials.

Drinks: Attentively made classic and modern cocktails, some by the carafe; curated sake and shochu lists, Ha Noi beer, and a limited, but focused wine list.

Go-to dish: Ground wagyu, thin egg noodles, tomato, miso, grana padano ($20).

Pro tip: At lunch, the pho noodle soup is the business.

Terry Durack is chief restaurant critic for The Sydney Morning Herald and senior reviewer for the Good Food Guide. This rating is based on the Good Food Guide scoring system.