Cornerstone, 3 Prince Edward Road, London E9 5LX (020 8986 3922). Dishes £5-£17. Desserts £10. Wines from £35

Great restaurants are rarely born. They are made. They are the accretion of details done right over time. They have to find their feet, and their hands and all the other bits of their metaphorical anatomy. Cornerstone, in east London’s Hackney Wick, does not feel like it went through any of this. It seems to have arrived in the world fully formed, which is all the more remarkable given the weight of expectation upon its shoulders.

Until very recently Tom Brown was the new best chef you had never heard of. I first clocked his name in the summer of 2017 when Nathan Outlaw put him forward for the OFM young chef of the year award. As well he might: Brown was his head chef at the Capital Hotel in London’s Knightsbridge, after a training which had taken him through some very serious kitchens at very great speed. He didn’t win that year, but it was clear from what Outlaw said that he would soon have his own restaurant and that it would be worth our time and our appetite.

So it has proved. A few weeks ago, Brown finally helped win an OFM award, when Cornerstone was named Newcomer in Food and Drink, a category voted on by our expert panel. I wasn’t there for the final judging. I had a braised otter dish to road test, or some festering, overpriced gastro-cataclysm to eviscerate. Something like that. In any case, I’d have had to place my vote elsewhere simply because I hadn’t been there.

Now I have been and it’s all very simple: blimey, Cornerstone is good. Fish cookery is tricky. There are hordes of people who worship at the altar of the raw ingredients; who argue that the less you do to them the better. They have a point. Seafood is delicate; best leave well alone and all that. Then again, if you know what you’re doing, how much better is it to take the good stuff and make it shine through wit, technique and good taste?

Take the “pickled” oyster. The inverted commas are mine, for while there is a lot of brisk acidity here, it is not so much pickled as dressed. That’s dressed as in haute couture. It is impeccably tailored. Yes, there is a bright, fresh and crisp, cooling herby liquor. But there is also a horseradish cream and the tiniest dice of celery, and finally a frond or two of dill. There is an astonishing amount going on inside such a small half shell. But the truly astonishing thing is that it does not overwhelm the oyster, which still speaks for itself. Give one of those a go and you know you are in safe hands.

So it continues. Raw gurnard is sliced thinly, laid out across a plate and dressed with sherry vinegar and the crunch of almonds and a little cream. It’s one of those dishes which is all about judgment. How much is enough and how much is too much? Brown understands the word “enough”. These two dishes make it all sound like a delicate pinkie-raised affair, but it really isn’t. A big fat homemade crumpet, sitting proud on the plate, comes stacked with a generous pile of nutty potted shrimps, dripping with spiced molten butter. There is a dice of gherkins to help you pretend this isn’t a total heart-stopper and, on the top, a tangle of kohlrabi in ribbons. It’s the thinking person’s crumpet. It’s what high tea would look like if it was served in a bordello.

A little closer to the nursery is a ripe, foamy pillow of cod brandade, speckled with fresh green herbs. It is piled with wild mushrooms sautéed in butter. In the middle, sitting pert and golden, just waiting to run, is an egg yolk, its surface dusted with salt and pepper. It is a dish so handsome it almost feels like vandalism to slip in the knife. But only almost: the yolk runs, the mushrooms meet the brandade and all is right in the world.

What underpins the cooking is a clear understanding of the essentials. A pristine piece of hake, all pearly flesh and golden skin and utter delight, is perfectly cooked. A beautiful fish has been shown respect. In the circumstances the lightly spiced pumpkin purée and the thyme dressing feel like the gorgeous velvet box in which a diamond ring is presented. And now I’ve gone off on one, which is what happens when the food is this good. Not that all the ingredients need to be such huge marquee names. A lowly wedge of celeriac is chargrilled and partnered with silky cod’s roe and hazelnuts. At the end we are presented with a skate wing, cooked to the point when it practically removes itself from the cartilage. It comes with a deeply savoury and luscious roast chicken butter sauce. Whisper those words to yourself: Roast. Chicken. Butter. Sauce. If you’re not sighing happily, then you are dead inside.

Brown recently appeared on Great British Menu, where his fish cookery made an impact. On his first outing in 2017 it was his desserts which got the attention and, having tried two of those here, I understand why. A mille feuille of pear with whorls of cream flavoured with Earl Grey tea, sandwiched between delicate circular tuile, is a seriously classy piece of work. It is bettered only by a blackberry and quince pavlova, starring a bulging meringue which manages the crunchy-chewy thing.

Is Cornerstone without blemish? Not entirely. Infuriatingly, the wine list has nothing below £35 a bottle which, frankly, is crass, the more so given this is Hackney Wick. The area may be undergoing major redevelopment. The building it occupies is a part of that. But this is still an economically mixed part of town. There are some who feel a restaurant of this ambition is completely out of place. I would argue it fits a mixed economy and that the food pricing is fair. The wine pricing is not (although I am told they are rethinking it).

Then there is the space. With its polished concrete flooring, industrial ceiling ducting and gunmetal-grey bar fringing an open kitchen, it can be bright and spacious on a sunny day. By night it could lean towards the hard-edged. Then again, what matters here is the cooking. In truth you should mostly be looking at your plate. If you’re staring round the room, you have completely missed the point.

Jay’s news bites

Riley’s Fish Shack, housed in a shipping container on the beach in Tynemouth, is a favourite of mine but has never had a mention in News Bites, so it’s time. The dedication to fish cookery matches that at Cornerstone, but the aesthetic is more rugged: mackerel wraps, lobsters, chargrilled squid, served in cardboard boxes. It’s open through the winter, storms allowing (rileysfishshack.com).

And a big hello to new mail order subscription service Books + Beer, which does what its name suggests. For £10 (plus P&P) they will send you a box containing a paperback in a genre of your choice, plus two craft beers. 50p per box will go to the male mental health charity Calm (booksplusbeer.com).

Following a number of deaths related to allergic reactions after purchases at food outlets, the self-proclaimed ‘healthy’ fast food chain Leon is getting staff at selected outlets to ask customers about allergens, when they order. They have also made allergen information much more obvious in store (leon.co).

Email Jay at jay.rayner@observer.co.uk or follow him on Twitter @jayrayner1