Reputations. Who'd want one? As much as they give established restaurateurs a leg up as one project seeds the next, what a weight to bear.

I say this because fans of the Mulberry Group's former projects, from Kettle Black to Higher Ground, have already pounced with frenzied, frothy mouths upon the group's latest double-barrelled offering: Hazel, which fills the upper two floors of the redbrick Richard Allen Building on Flinders Lane, and independent bar, Dessous, which is underneath.

I waited three weeks until FOMO got the better of me. But Hazel isn't ready yet. She might not be for some time. I'm telling you this so she doesn't earn a reputation of the wrong kind.

We may live in a time where the restaurant-bar line has been smudged into obscurity. But restaurants and cafes, Mulberry's stock in trade, operate in parallel universes. Cafes might be serving restaurant-quality food, and getting you soused on serious wine lists before noon, but when did you last sit down to a seven-course brunch? The logistics are night and day. It shouldn't be underestimated what a learning curve Hazel is.

That's not to say she won't charm you straight away. Hana Hakim's design might have been based on a heavenly Liberace stage set: plump Deco stools ring the bars, twinkling chandeliers dangle overhead, gilt mirrors grace snowy walls and white-cream horseshoe banquettes make me intensely nervous reading a menu featuring 'nduja and beetroot salad.

Lunch or dinner can be bracketed with twisted negronis, accessible blanc de blanc for $60 or Bollinger for $240 at the ground-floor bar. When you ascend to the dining room or the kitchen bench for a close-up of ex-Rockpool chef Zac Nicholson's fiery ovens, the menu reads like a bestseller, even if alarm bells do ring at its heft (currently it's 31 dishes, plus desserts and cheese).

Read it and feel your engine rev for roasted oysters with chicken sauce, and king george whiting crudo spiked with fresh horseradish. There's an entire bracket of things on toast; the friendly comfort of fettuccine with greens; then lamb chops and duck breasts and springy veg medleys. How can you go wrong?

The short answer might be: doing all 31 of these things at once, supported by a floor team ranging in experience from ex-Merivale pros like general manager Ryan Bresler and venue manager Nathan Matthew, to fresh young charges as green as the bathroom's palm frond wallpaper.

Reality versus expectations? Hazel is pitchy. And yet, you can see its path to glory laid out. Slashing the menu might be a smart start, freeing the kitchen to make remaining dishes every bit as good as they sound.

No issue with a smoky scoop of French onion dip, delivered with cereally, buttery crackers and the house's pro-produce philosophy. Nor malty sourdough whose thick layer of butter is kefir-cultured and draped with premium anchovies, or the whiting crudo, with a good slug of fruity oil and lemon zest joining the horseradish.

Less sure-footed, salty chicken sauce bullies those roasted oysters, while our 'nduja toast is thick sourdough that's grilled, but left to cool – no crunch, no char, no warmth to activate that excellent house-made salami topped with a few pickled pipis.

We're back on track with a Jenga stack of asparagus dusted with parmesan, chased by thick, strappy fettuccine whose rusticity and chomp reflect how you might make it at home, especially tossed with wilted silverbeet, chilli and garlic, but that's somehow part of its appeal. For $22? I'm not so sure.

The thing about simple, produce-driven menus is they aren't simple. Every second counts. It mightn't be a napkin-tossing disaster that grilled lamb forequarter chops, nicely razzed with chimichurri, lack a caramelised crust, and that there's no texture variance from skin to meat in the balsamic-glazed duck breast. But it's frustrating. Like viewing a beautiful picture, blurred.

Praise be, then, for a final act that brings laser focus, and with it the belief that Hazel will come right. Sous chef Brianna Smith, late of South Australia's Summertown Aristologist, makes her own brie, and the wheel's pungent subdermal layer escaping across the plate is dinner redeemed.

Team it up with pastry chef Rosemary Andrews' treacle tart, executed with knifepoint precision, from its fine, shattery crust to its tensioned bitter-sweet flavours, and you see the shape of Hazel emerging from the mist.

I can't wait to see what else they can do with some room to breathe, and a crew pulling as one. But I will wait. Perhaps you should, too.

Vegetarian All dietaries can pick around the menu.

Drinks The 120-bottle list caters to lovers of old and new, big houses and small.

Cost Entrees $12-$28; large $22-$70.