The Blue Door's menu is a revolving door

Before the snacks come to our table at The Blue Door, out comes the bread. A mix of slow-maturing wheat and malted rye, it's a two-for-one, featuring slices of today's bake and delicious rolls made using yesterday's "spent loaf".

The butter is cultured, and with it arrives a board loaded with four lumps of salt and a steel grater. The sound of rock grinding on metal punctuates the early moments of your meal as the tables around you blitz salt to a powder to sprinkle on their butter, while staff mention that the crystals – from Austria, or perhaps Bolivia – are the first nod to what this place is all about: provenance.

But The Blue Door, tucked away in a Surry Hills back street and seating just 18 diners, is no globetrotter. Rather, it (mostly) homes in on NSW, pitching an approach that's built on produce from suppliers whose farms chef Dylan Cashman has visited, then backing it with a determination to use whole animals, and to stay seasonal by changing the menu every week.

One week, the plates that make up the opening Snack Attack on the tasting menu might feature ruffle-edged crackers topped with pureed carrot and nigella seeds, addictive pieces of crisped, salted fish skin or slabs of thinly sliced potato, fried and loaded with mayonnaise, chives and cured yolk; the next, they'll be entirely different.

Needless to say, this is a venue with high ambitions. Run by Cashman and sommelier Angelica Nohra, The Blue Door is a second take on a concept that originally debuted on the Gold Coast before closing and relaunching here post-lockdowns. Like the original, the restaurant takes its name from its entrance, a door painted an appealing shade of cerulean.

Behind it, just a few tables and a long, comfortable banquette fill the space in front of the open kitchen. It's a beautiful, simply appointed restaurant, with shades of grey accented by blue linen and Riedel glassware.

And when the second course – a pile of raw and cooked Moreton Bay bug meat tossed with finger lime, topped with crunchy green slices of celtuce (celery lettuce) and cucumber, and finished with a celtuce and buttermilk dressing – comes out, the ambition in the approach is matched by the execution.

As it's served, a waiter name-checks the suppliers and pours the first glass in an all-NSW wine pairing ($85), a skinsy Vinden gewurztraminer from the Hunter.

A follow-up course, which sees frisee from Duck Foot Farm in the Southern Highlands grilled over coals, then plated with pickled radishes and crisped duck skin, is a cute little dish, too, meaty and fresh.

Throughout, there's an enthusiasm for the food and wine that's infectious, and a real belief in the philosophy. And yet, as the meal progresses, the early promise begins to fade just a little. The floor staff, warm and personable, might strain to recall the vast number of elements in every dish.

Where you might expect the meal to build towards a climax, you're instead served half a grilled chicken thigh with some stalks of cauliflower blossom and a slightly grainy almond sauce.

You may question, too, whether a single croquette riffing on chicken pie, meticulously sourced though it is, would be better suited as a snack at a wine bar than as a course on a $159 menu.

You think back to the global salt selection and wonder if it fits with the strong local focus. Then there's the soundtrack of tame pop covers.

The most celebrated degustation restaurants bring exceptional technique and clear ideas to bear on pristine produce sourced from mindful producers, then present the courses in such a way that they form a cohesive whole.

The Blue Door has noble pursuits and is clearly nailing the sourcing, but I wonder if Cashman's time might be better spent refining his ideas rather than pushing so hard to change his menu so frequently.

Right now, he has his kitchen making two kinds of bread; shaping dumplings for snacks; baking sweet meringue to pair (oddly) with confit duck and beetroot; dicing apple to go with a tiny, sticky date-like cake; prepping petits fours and much, much more. Next week, those tasks will change again.

As a former chef, I can tell you that while scaling up just a few preparations is simple, preparing small quantities of many complex elements is very tough indeed. In this time of staff shortages and high overheads, why not give your team less to do and let the dishes develop? Start with a core of good ideas and build around them, perhaps?

Maybe then those hits, which Cashman clearly has in his repertoire, would flow a little more steadily and a promising newcomer might begin to truly flourish.

Vibe: Intimate fine diner with a casual demeanour and lofty ambitions

Go-to dish: Blue Door Snack Attack (part of $159-a-head set menu)

Drinks: Mostly NSW wines with a few favourite French drops, including champagne

Cost: $318 for two, excluding drinks

This review was originally published in Good Weekend magazine