I know it's only the first week of July but sod it, I'm calling it early: Sixpenny's new tart is the snack of the year. And by "snack", I mean what chefs used to call an "amuse-bouche" and by "tart", I mean a crisp pastry shell laced with kombu and covered in black truffle emulsion.

Roast Jerusalem artichoke, soft and nutty, sits in the middle, enhanced with a miso paste made from the lumpy tuber's own skin. A little shake of malt powder adds toastier notes. The complimentary starter represents all that Sixpenny is about in 2022 – refined comfort and flavour built on fermentation.

Food rich in style and substance has long been a trademark of the restaurant, where local couples have been celebrating birthdays and why-nots for more than a decade. An incongruous Stanmore address is a big part of the charm. What's that behind the sheer curtains of an old brick corner site? Why, it's one of Australia's most relaxing ways to spend three hours and a reminder of how fine-dining should be done. Salve for the soul at $215 a head.

The main dining room is all quiet grace and radiant timbers, a place of artisanal ceramics, fine glassware and botanical illustrations, which also feature on your take-home copy of the seven-course menu.

From a central wooden waiters' station, sommelier Tommy Pajak opens leesy, cheesy Jura savagnin and pours Andrew Thomas Wines' 2021 Six Degrees Semillon by the glass ($17). Restaurant manager George Papaioannou remembers that the last time my partner and I were ordering champagne from Pajak, we were toasting our anniversary.

This time we're here because I have a hankering for food transformed into something more delicious through koji – the mould-inoculated grains that give us soy sauce, sake, mirin and other magical ways to season a dish.

Head chef Tony Schifilliti (formerly of Barangaroo's Cirrus) joined the Sixpenny team in November and the guy is koji-obsessed. A new ferment feature wall near the kitchen is home to a few dozen jars labelled along the lines of "barramundi paste", "doubanjiang" (spicy broad and soy beans) and "black garlic miso".

The latter adds a gently sour undercurrent to fresh (fresh!) borlotti beans, lightly braised and mixed with plenty of dill. One perfect sashimi-grade paradise prawn is perched on top and showered in tiny curls of bottarga made by leaving rice koji and salmon roe to get to know each other intimately for eight months. Clever. Warming. Engaging. Fun.

Sixpenny owner-chef Daniel Puskas, who co-founded the restaurant when he was 30, is still very much a part of the day-to-day service, but it's largely Schifilliti's menu. Puskas acts as a mentor, providing guidance, tasting dishes and coaching staff – sort of like a less intimidating Marco Pierre White any time the shouty British cook pops up on MasterChef.

This measured approach creates some truly wonderful moments. Pan-fried Murray cod has rarely been more creamyfleshed and crisp-skinned; it is weaponised with macadamia puree and a midnight-black sauce of cephalopod ink and offcuts. The ink is fermented, of course, as is the accompanying mound of grilled mustard greens dressed in a sour paste made from herb trimmings. The "better" parts of the squid are spooned with a frothy koji butter, sitting pretty on sauteed discs of broccolini stems fragrant with green garlic oil.

Roasted wagyu rump cap makes an appearance for the final savoury course, sticky with marsala and mustard jus. A great bit of steak, but it lacks the long, delicate flavours of previous dishes. Maybe I've become too accustomed to ferments by this point.

Mead vinegar custard, however, has been a signature for several years and can take its place on the Mount Rushmore of Sydney desserts alongside Quay's snow egg. Raspberries are blast-frozen and shattered into individual drupelets to pop like sunshine in winter against the spiked custard and a strawberry consomme. There isn't a better balancing act of sweetness, temperature and texture in town.

Sixpenny is booked out three months in advance, so if you don't have a reservation already, that Jerusalem artichoke and truffle tart might be gone by the time spring rolls around. There's always next winter, though. 

With Schifilliti in charge of the pans and jars, and Puskas coaching the next generation of talent, I feel Stanmore's little-fine-diner-that-could is just getting started. Here's to another decade of seriously smart cooking rooted in Australian tradition and age-old techniques.

Vibe: Trailblazing, refi ned, sustainable comfort

Go-to dish: Murray cod with macadamia and mustard greens (as part of a seven-course tasting menu, right)

Drinks: Extensive selection of rare and gratifying wines, plus a few aged Australian favourites

Cost: Tasting menu $215 per person

This review was originally published in Good Weekend magazine