You don't need any sci-fi devices to travel back in time, you just need melon soda and coffee jelly. These sweets are a charming staple of kissaten – old-school Japanese cafes from the country's Showa era (1926-1989) – and they're on the menu at Wan in Mascot, which turns to these retro coffee shops for inspiration.

This likeable eatery isn't purely about flashbacks, though. "We refresh the kissaten," says co-owner Elvan Fan, who runs Wan with pastry chef Carol Xu. The duo also operates Moon & Back in nearby Rosebery, another Japanese-inspired venue, but Wan's influences go beyond the East Asian country.

Fan is from Taiwan and that's shaped the eatery, too: Wan's terracotta wall is ornately configured to resemble the iron-window patternwork from her homeland, and the cool tang of the cucumber salad recalls her times eating there. "When you go to a small noodle shop in Taiwan, usually you order a lot of cold dishes before noodles," she explains.

Wan's name (which means bowl in Chinese and Japanese) captures what they're doing. It symbolises Eastern culture and the wide-ranging things you can scoop or ladle into their namesake: soups, noodles, nostalgia-sparking desserts. "We can put everything in a bowl," she says. They even have a cool bowl-shaped table at Wan to reflect this.

It's on brand, then, for the eatery to serve many excellent things in its signature wares. There's the bracing cucumber salad splashed with black vinegar and chilli oil, the tingly, citrus spice of "piri piri" karaage chicken with sansho and yuzukosho mayo, and flash-fried edamame that's vividly seasoned with wasabi and ramen salt (you can taste the full-flavoured punch of the peppery, roast onion and sea salt blend).

There's also the rich, cheesy, starchy comfort of pork "hamburg" rice: hot, gooey provolone cascades over the Akitakomachi grains, while the umami-loaded serve of pork belly patty is flavoured with caramelised onion, miso butter and a sunny egg yolk.

"It reminds us of how we always eat rice burgers," says Xu. "It's kind of like a deconstructed rice burger," adds Fan.

Some menu highlights aren't featured on bowls at all – like the spectacular corn ribs. They're heavily seasoned with seaweed and a "nacho" (dehydrated cheese) powder that tastes like the most next-level version of Dorito's Cheese Supreme. It's the most dangerously snackable thing I've eaten in a long time. 

"Kissaten shouldn't just be lunch and dinner," says Fan. So Wan has optimised its menu for late-afternoon hunger cravings, by offering yakisoba pan. These noodle-filled hot dogs, topped with nori and squiggled with mayo, are emblematic of many Western-inspired dishes that have since become Japanese staples.

Like coffee jelly with a generous topping of cream, which is now a time-tripping kissaten favourite. At Wan, darkly roasted beans and a sprinkling of salt add a vital kick to this classic dessert. 

For their menu, Xu and Fan drafted in Kei Tokiwa, who previously worked at Chaco Bar and Sekka Dining – Japanese restaurants they're both fans of. Together, they've created a knockout menu, big on flavour and surprises.

The space feels like a contemporary remix of kissaten: it has the cosy hangout feel of yesteryear coffee shops, while the playful design (mysterious holes to peer through, the bowl-resembling table) configures it for the Instagram age. Wan, like a well-crafted bowl, successfully contains everything. 

The low-down

Main attraction An updated kissaten given a Taiwanese twist. There are throwbacks (like the cherry-topped melon sodas), and inspired reworkings of classics, too. Instead of a typical Taiwanese beef noodle soup, you can order wagyu-flavoured somen in a Taiwanese chintan soup base. A Japanese milk mochi dessert is redone to resemble stretchy, jelly-like warabi instead of traditionally doughy mochi rice dumplings.

Must try The architectural corn ribs, dusted in seaweed and a deeply flavoursome cheese seasoning.

Insta-worthy dish The retro-looking melon sodas or the coffee jelly (if Archie comics were ever set in Japan, this is what its teen characters would order).