You know you're too early for dinner when you end up in the street press photos. And day one, service one was too early to be at Lesa. In my defence, Lesa was late. The new upstairs set-menu expansion of Russell Street's gun wine bar, Embla, has been in the works for more than two years. Curiosity won out.

If it also got the better of you in those first days, or even weeks, I'd recommend a second innings now. Reputation can be a millstone for established players. And the double-winner precedes of Carlton's Town Mouse (RIP) and Embla for Kiwi imports Christian McCabe and chef Dave Verheul must have registered a neck-crushing weight as they worked out what to do for round three.

When Town Mouse opened in 2012 it kicked some holes in our known dining universe with its rigorously engaged service, and a high-low menu of things both technique-driven and fun delivered in space that didn't even have proper backed chairs. Then came Embla, which stole the show offering straighter dishes (roast chicken, tartare, pâté and bread) but drilled deep into the core of those classics and used raw fire power to create world-class versions.

Where could they go? We knew they were heading upstairs with their offering (figuratively and literally). And with the closure of Town Mouse last year it seemed feasible that favourites might transfer here as a set menu. But Lesa has emerged as an all-new beast.

It's more luxurious, but not necessarily more formal. There's finery here. The room is as low-lit and woody as it is downstairs, with a stunning emerald-tiled kitchen at its heart. But most of the trappings – a few blue velvet chairs at one group table; a huge floral curtain blocking stairwell draft and silver coaster swans – have been nabbed from antique shops. It's more like a room doing fancy dress rather than a fancily dressed room.

The food is definitely new. You've seen Verheul work with a lot of fermented elements before, and favour a herbal, savoury and subtle flavour wheel that mightn't always hit an instant satisfaction button in your brain. That was magnified on the first trip to Lesa.

There were winners. Flounder tartare, shrouded in hazelnut and green almond dust was earthy, respectful to fish and bright from an acidulated broth; the veal tartare had elegant edge, even if the flavours of fermented tomato made you reminisce about the '90s, and its shield of pickled saltbush leaves camouflaged it like a hunter's hide. Then, you could still see Verheul working out a new groove. Now, he's relaxed a little, and staggering first steps are making sense.

You can do two courses at lunch and for pre-theatre, but the full thwack of the $120 menu is worth settling in for. It starts with snacks. Heart of an artichoke bloomed in oil swabbed in cheesy ricotta; one broad bean, charred and chilled and so young you can eat it pod and all. Of two tarts, petals of pickled cucumbers over a warm buttermilk cream in a crisp tartlet has it over the shaved radish mounted on butter and a fragile rye cracker.

The flounder dish has evolved to a spring pea crunchy arrangement made salty from a dehydrated mussel dust.

The arrow squid, always texturally trippy having been frozen and shaved into wide wobbly sheets like rice noodles, and paired with clam stock-washed braised parsley, acting as green veg, is somehow richer, warmer, the chlorophyllic greenness and buttery flesh united as well as any classic pairing.

There are dehydrated potato strands tumbled through a cacio e pepe liquor that registers all of those heavy elements, yet remains light.

Verheul is cooking up here like a French auteur. The wines can be just as cerebral, from the intensely herbal Joy riesling (verging on vermouth) from the Adelaide Hills to an approachable-to-all-tastes organic Cabernet Franc from New Zealand. Capable sommelier Raffaele Mastrovincenzo, last at Kappo and IDES, is there to be a necessary spirit guide when ordering bottles or relaxing into a few dish-matching pours.

Fair warning: dishes are still largely two-tone, visually sparse. But if you care for food that stands up and asks for a little attention, Lesa plugs a gaping hole in the current dining spectrum.

There's less showy fire, but ample thought, and the originality is a breath of fresh air.

Creamy chicken mince porridge shrouded in black fermented chestnuts (with optional caviar – take it) is quirky comfort.

A pork chop, frightening on day one for its unusually pink, plush texture resembling rawness, has tightened and offers a skein of crackle, sweet, mellow fat and tender meat contrasting a kale crisp and umami-filled buckwheat miso in a sauce.

There's white chocolate cream, electric with ginger and sharp fermented raspberries, then a cleansing green apple and camomile ice-cream. None of this looks as warm as the service you have come to know from this team. But it's delicious.

Lesa has finally, finally arrived. It's a package that won't be for everyone. But everyone else can have Embla.