Omnia, the pop-up restaurant designed for executive chef Stephen Nairn to flex his culinary muscles ahead of the opening of LK Hospitality's enormous Capitol Grand development later this year, opens today on Toorak Road.

It's a testing ground for the yet-to-be-named all-day diner set to be the first of three restaurants opening in the $800-million South Yarra development later this year. But Omnia, which loosely translates from Latin as "prepared for everything", already feels like its own entity.

"We've put a lot of work and a lot of thought into it," says Nairn, whose CV lists Vue de Monde and New York's Eleven Madison Park. "It's got great bones and a great energy already."

Occupying the space that once housed Hagger's 25 Toorak Road restaurant, the 36-seat dining room has been kitted out in natural materials – leather, marble and timber in hunter green and brown – with a number of David Bromley works hanging on the walls, and there's a similarly colour-schemed Garden Bar (led by ex-Lume bartender Orlando Marzo) and courtyard behind.

Despite Nairn's fine-dining pedigree, Omnia sits firmly in bistro territory. The menu – "European flavours, high-quality ingredients, sustainable and seasonal" – ticks off classics such as steak tartare (served here with smoked egg yolk and pomme gaufrettes), whole flounder with brown butter, lemon and capers, and lamb rump with eggplant, tomato and lentils.

The desserts by pastry chef John Demetrios (also ex-Vue de Monde) plot a fine-dining course – more frozen mandarin with glazed soft meringue than chocolate mousse.

Tom Hunter (ex-Oter and Coda) has put together the 150-bottle-strong wine list, which focuses on smaller Victorian producers (such as Patrick Sullivan and Timo Mayer) alongside a selection of burgundies and barolos and other international benchmark wines.

Although it's slated as a year-long pop-up, if it goes well there's every chance Omnia will stick around.

Open Tue-Sat 5.30pm-late.

25 Toorak Road, South Yarra, omniabistro.com.au