Call this a canteen? I was expecting trays. And a counter where you line up for service. And chefs dolloping ladlefuls of food onto your plate. But no, A1 Canteen is more your post-canteen canteen. It is, at least, A1.

This high-ceilinged, light-filled space in Chippendale is a room for now; an all-day diner that echoes the mighty Cumulus Inc in Melbourne with its breakfast, lunch and dinner democracy.

Automata's Clayton Wells has walked across the laneway – along with talented head chef Scott Eddington and spirited manager Rachael Trewin – to open in The Old Rum Store.

Interior designer Matt Darwon came along for the ride, keeping the textures concrete and stainless steel and the vibe chilled. There's a coffee window upfront, with cafe seating barely divided from the dining space, softened with curved booths and banquettes, and a long, low, bottle-lined service bar.

The food and mood change constantly from dawn to dusk. Breakfast runs from a theatrical granola with black sesame paste and mauve rhubarb yoghurt ($12) to a blinder of a grilled mortadella and fried egg roll ($12) with fermented chilli and the crunch of fried shallots.

Breakfast is a tough gig for a chef, but A1 makes it look easy. Curdy, curried, scrambled eggs ($17) come with LP's bespoke pork sausages, which are just what you want from a breakfast sausage but never get.

Cruise in for a weekday lunch and choose a main and any two small salads ($22) – OK, so that's very canteen – or maybe a sandwich ($12 to $16), built tall with chicken and chiffonade lettuce or leg ham and sauerkraut.

It might sound a bit thrown-together, but this stuff has been worked and reworked until it works. I'm thinking here of the muffuletta, a pressed baguette of olive, mortadella, salami, ham, provolone, peppers and artichokes ($14). Like its Provencal cousin, the pan bagnat, it usually ends up as something nasty and soggy at the bottom of a picnic basket, but here, the right bread, rich layering, and those deal-breaking artichoke hearts make it an out-and-out success.

At dinner and weekend lunch, the vibe changes to bistro, and the rob roys and old-fashioneds come pre-batched and bottled. Automata's fried anchovy-stuffed olives ($10) are so moreish that I account for seven without even realising.

There's drama in a daring pairing of two of the reddest things on the planet – blood and beetroot – in a deeply rich, sweetly savoury, house-made blood cake under swathes of pickled beetroot ($22). A meaty whole flounder awash in peppery espelette under a shower of crisp curry leaves ($40) is good to share.

The dinner winner is lamb tartare ($22) that's like a lush kibbeh, the gnarly, hand-chopped meat entwined with eggplant and sumac on a pool of tahini yoghurt, with slices of pickled green almonds on top that look like evil eyes.

Wines are as natural as the dishes, and a 2017 Sud de Frank "White" ($60) brings a zesty, organic blend of sauvignon blanc and petit manseng grapes from the Adelaide Hills and New England to the table.

Desserts are freshly composed, with roasted quince and pistachio sorbet ($14) proving to be as lovely a seasonal pairing as it sounds.

Egg-and-sausage breakfasts, door-stopper sandwich lunches, big-flavour bistro dinners and high-level snacks – it's got the lot. Except for trays.

The low-down

Vegetarian The choice isn't overwhelming, but what's there is as thought-through as the rest of the menu.

Drinks Single O coffee, pre-batched cocktails, cold-press juices and a discriminating list of naturalish wines

Go-to dish Lamb tartare, eggplant, tahini yoghurt and sumac, $22

Pro tip After 10am, you can add on a beautifully balanced pre-batched negroni

Terry Durack is chief restaurant critic for The Sydney Morning Herald and senior reviewer for the Good Food Guide. This rating is based on the Good Food Guide scoring system.