"Buona sera" says Laura, opening the door to Fratelli Paradiso. "Good evening," I reply. "Buona sera," she says again, with greater emphasis.

It's that firm insistence on sharing all things Italian that has won Fratelli Paradiso its hard-core legion of regulars, ever since Marco Ambrosino and brothers Giovanni and Enrico Paradiso opened its doors in 2001.

To celebrate the restaurant's 16th birthday in early September, they closed for nine days – not to party, but to work, transforming the cafe side of the operation into a more sophisticated dining room with curved booths upholstered in tan leather, textured hessian walls, ribbed walnut panelling, and metallic 1960s-inspired lighting.

But that's just the stuff you can see. What you can't see is the new cool room in the basement, and the on-site bakery oven, now removed to the kitchen.

It's so rare for this all-day, every-day tratt to be closed that the number of bewildered people wandering around Potts Point – like a bunch of MPs locked out of parliament – was almost comical. When the doors reopened, the diners returned as naturally and inevitably as the tide, filling every available space, greeting the staff – Gigi, Mark, Lorenzo, Laura, Vinnie, Jason, George and the rest – with kisses.

So what's the big deal? It's not as if you can get anything you want here. This is the tightest menu in town, just 12 tweaked Italian classics scrawled on the giant blackboard. And it's not exactly innovative: the calamari Sant'Andrea has been on the menu since day one.

There's no celebrity chef swanning around, either; with the hard-working Akira Urata and team kept firmly in the kitchen. Nor can you book – it's walk-ins only – and nor is it cheap.

But there's a quiet elegance about the food now, in the way the vitello tonnato ($25) slowly reveals itself in layers, from its crown of house-made potato crisps to the paper-thin discs of pink veal backstrap that conceal the creamy tuna sauce beneath. 

Saltimbocca ($31) is a simple pan-fry of flattened pork loin in a winey, sage-flecked buttery sauce flavoured with dried prosciutto, the wilted, mossy spigarello (Italian leaf broccoli) tucked away out of sight. Risotto ($26) is wet, wavy and madly buttery, studded with gravelly Italian sausage, mushrooms and goat cheese.

Spaghetti with scampi ($32) is al dente but not ruthlessly so, with a fresh-tasting, bisque-like tomatoey sauce threaded with scampi meat and a whole, split scampi for added drama. To end, torta di pere ($14) is a soft, sweet and innocent little pear cake with a puddle of syrupy saffron anglaise.

Wine is a major part of the charm here, with an invitingly all-Italian list revelling in low-intervention and so-called orange (skin contact) wines.

The 2016 Monastero Suore Cistercensi Coenobium ($13/$65), a uniquely minerally white made by the sisters of the Cistercian Order just north of Rome, is typical of its level of engagement.

The magic here comes from the heavily edited menu, the considered wine list and all that sensory reassurance in the hiss of the espresso machine, the clatter of plates, the loud chatter, and the greeting and farewell at the door.

There's a social ease to Fratelli Paradiso, good manners delivered with high-speed energy. They speak Italian, sure, but mainly they speak the language of dining, of hospitality.

The lowdown

Best bit: The new low-line booths, the old elbow-to-elbow tables

Worst bit: I've never been mad about the coffee

Go-to dish: Scampi spaghetti, $32

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.