Coppi, St Anne's Square, Belfast (028 9031 1959). Meal for two: £60
Mourne Seafood Bar, 34-36 Bank Street, Belfast (028 9024 8544). Meal for two: £70
Ox Restaurant, 1 Oxford Street, Belfast (028 9031 4121). Meal for two: £110
The exterior of Ox in Belfast is much like my soul: black and featureless. There is a large plate-glass window which looks into a sparsely furnished dining room. It appears to have taken its design cues from a hyper-efficient car workshop in Dusseldorf. It is all hard lines and hard surfaces; if the food game doesn't work out the space would make for a jolly nice torture garden. Nowhere on the restaurant frontage is its name. Perhaps letters were judged to be messy. Then again they hardly need to advertise. During my three days in Belfast almost everybody I met talked to me about Ox: had I been there? Was I going there? And what did I think? A cab driver took a detour just to show me where it is. I hadn't asked him to do so.
Ox is a collaboration between the former head chef of James Street South and the manager of Deanes, two of the city's better-thought-of places. Local boy Stephen Toman and Brittany-born Alain Kerloc'h have done their time, served their apprenticeships at fancy joints in France like L'Arpège and Taillevent, where heels are clicked and cloches lifted.
What was striking in Belfast was the palpable sense that everyone wants it to be good. In London an opening like this would be a cue for bloodletting and Olympic-quality bitching, rumour, innuendo and sneering, and that's only from the chef's mother. Not, apparently, in Belfast. As the admirable Belfast food blog forked.ie put it recently: "At times here in the North we're still like one big dysfunctional family… happy to knock seven shades of shit out of each other but stop midway through the fight to join together against the outsider who happened to make eye contact at poor wee cousin Janie."
I know this to be true. I have been that outsider. I have said the bad things, and felt the ire. There is local pride, and not unreasonably. There are many cities in the UK where the dining options would be exhausted by lunchtime. On the first day. I knew early on that I wouldn't have enough Belfast mealtimes in which to visit all the places I wanted to try. The newish faux-Georgian Saint Anne's Square development, for example, is wall to wall new restaurants. On one side is an Italian called Coppi, launched by a veteran Belfast chef and restaurateur called Tony O'Neill. It looks like a Jamie's Italian on steroids, all heavy wood tables and white tiling. The intention is similar. It is meant to be a casual place, lighting sparklers rather than fireworks.
Most of the small plates – some pork and fennel sausages, strips of breaded chicken with an underwhelming romesco sauce – are a little a bit ho and a little bit hum. But there is a wood-fired oven for terrific charred breads, and a selection of steaks supplied by the extraordinary local meat producer Peter Hannan, who ages beef from shorthorns fed on clover, in a chiller room walled in Himalayan salt. Yes, really. Apparently the salt acts as an antibiotic.
I've tried the beef, and it is something special. It has a depth of flavour and dense texture without that "something just died in the corner" flavour you get with less-cared-for muscle. Best of all at Coppi was a stonking duck pasta dish, for a very reasonable £12.50, of fat ravioli stuffed with a fine ducky ragu, overlaid with more of the same, the whole spun through with fat flakes of crisped duck skin. It was deep and outrageous and completely unfinishable. Naturally I finished it.
Less happily, next door, is the House of Zen. It's the sort of fancy Chinese restaurant where they keep trying to give you a knife and fork, and all the money appears to have gone on faux Oriental screens and downlighters. The menu reads overwrought and sugary so I played safe by ordering dry, skinless crispy duck, and a beef in black bean sauce that left me clicking my tongue against the roof of my mouth just to kill the sensation. Service is of the distracted kind that results in you getting up to pay your bill at the front desk just to speed your exit.
It makes more sense when in Belfast to eat seafood, which I did at Mourne Seafood Bar, a much-loved local landmark situated in what feels like an old boozer near King Street (there is another outside the city at Dundrum). I ate pristine rock oysters, some plain, others with a julienne of cucumber and pickled ginger. There was a rustling bowlful of salt and pepper squid, and the kind of hefty seafood chowder that makes you wish it was colder outside. Each of these was a few quid, and while there are more pricey main dishes from a changing blackboard menu, no one could ever accuse it of being expensive.
And so, on the last night, to Ox. However austere it may look from the outside – and however obvious the ambition of the kitchen – it isn't up itself. Nobody bows. There are no stupid formalities performed because someone was so taught by a scary maître d' who could not be disobeyed. They want you to eat well with the minimum of fuss. Much of that applies to the food, too. Starters can read on the complex side – quail, white asparagus, fresh almonds, cherries, for example; or scallop, egg, curry, hazelnut, cauliflower – but they eat very simply. It's about top-quality ingredients to which the best things have been done.
The quail has been boned and glazed and roasted, the asparagus parboiled. There are fresh white, crunchy almonds and stoned cherries. It is all very balanced. Ditto gloriously sweet scallops seared until the protein is just set, with the crunch of cauliflower and nut. Even a plate of crisped Iberico ham, with dollops of a truffled custard, does not feel like good ham wasted. It is salt and soft and sweet and earthy.
If anything the mains, priced in the mid- to high teens, are simpler. The most showy thing in a plate of local Mourne lamb – some loin, a chop, a kidney, all of them served pink in the right way – is an ultra-smoky aubergine purée. A piece of beef fillet seasoned with a little lardo, the famed Italian cured piggy back fat, is a great piece of meat cooked by a kitchen that knows what it's doing. Rabbit comes with the sweetness of apricot and unctuousness of long-braised pig cheek; pollan, a local herring-like fish, is accompanied by cockles, artichokes and violet potatoes.
The great technique is disguised by superb ingredients. It is therefore unsurprising that desserts – a white-chocolate parfait with summer fruits; marinated strawberries with a sharp limoncello jelly – are overshadowed by a plate of well-kept local cheeses. There is also a thoughtful wine list with lots of choice by the glass and 50cl carafe, at prices which encourage experimentation.
It is easy to get carried away, to overstate what is going on here. Is Ox on a par with the very best in Britain? Absolutely not. But, for all the adoring local chatter, it doesn't feel like it's trying to be that. Ox simply wants to be best in class and then some. It wants to celebrate the best ingredients on its doorstep, and do it with unstudied professionalism. On those terms it has more than achieved its goals. It does not need to show off. Ox knows it's the most interesting thing to happen to Belfast in a long while. And the city seems grateful for it.
Email Jay at jay.rayner@observer.co.uk. Follow Jay on Twitter @jayrayner1
• This article was amended on 23 July 2013 to remove a reference, in the sub-heading, to Belfast as the "Irish" city.