48 Newman Street, London W1 (020 3667 1445). Meal for two, including drinks and service: £100

I have located the perfect country pub. It's a place where the cooking is shorn of dreary metropolitan clichés and posturing, where the choice of ingredients flows with the seasons, where you feel the Lawrencesque throb of nature and appetite working as one. As with any serious country pub, it's the kind of place where you could misplace a whole afternoon. And the best thing about it? You don't have to wade out into the country to find it. The Newman Street Tavern is on a corner overlooking a dusty building site just north of London's Oxford Street. Result.

I have nothing against the countryside. Some of my best friends live there. A lot of my working life involves stumbling across rutted farm fields wearing inappropriate footwear, like a character from some Howard Jacobson novel. I can do outdoors. But I'm much better at cocktails and central heating. Still, I do like the approach to food that "out there" can bring. The menu at the Newman Street Tavern sums it up perfectly. I have the paper in front of me and it feels like a place of safety. I'm stroking it. It's a bunch of ingredients – wild garlic, sweet cured trout, brown crabmeat, gulls' eggs – which bellow "Eat me!"

To all of these things chef and partner Peter Weeden does only what is necessary. That crabmeat arrives mined with pebbles of rosy roe on a thick-cut piece of warm buttered toast. It is all the richest, most intense bits of the crab, with a squirt of lemon to make it decent. Another piece of toast is smeared with laverbread, that glorious Welsh seaweed gunge which has all of the iodine and umami kick of its Japanese relatives. On top are two slices of crisp-cooked, dry-cured bacon. And then, to cool everything down, a still-warm boiled gull's egg, with a yolk soft enough to be spread.

An onion tart is where the kitchen's serious chops become obvious. If I tried to make pastry as stupidly thin and delicate as this, my kitchen would be littered with debris. I would be found sobbing in a corner, covered in pastry. This is a magnificent piece of work, the shell filled with a soft-sweet stew of tangled onions.

They do fish here, but we didn't. They had Blackface lamb and suckling kid. (The meat comes in on whole carcasses and is butchered on site.) Plus, they understand the imperative of fat; that fat is where all the flavour is. Their rounds of sweet suckling kid, the meat enclosing pearlescent jellied pebbles of the best fat, with butter-sautéed St George's mushrooms, are why I belong to a gym. They are why I wear a headband and bash away at the treadmill four times a week, arriving precisely nowhere. I do that so I can eat this. There are tiny ribs and a little bit of the belly. The Blackface lamb comes with some loin and belly and one large chop, and a proper ribbon of its own bronzed fat at its back, and tastes of a life properly led. Underneath there are salty-bitter sea vegetables, a little monk's beard and green frondy, crunchy things I cannot identify, but which I welcome all the same. There's grilled fennel with lemon and parsley and nutty little Jersey Royal potatoes.

There are two floors of solidly built pub, the walls covered with art of occasionally dodgy quality which somehow works. There are tall windows to let in the light and cheery staff to add to the lightness, and lots of wines from interesting places – wine of the month was a heavy-browed red from Turkey – many available by glass and carafe.

Obviously we did not need sticky toffee pudding or a sweet blackthorn jelly surrounded by a deep moat of Ayrshire cream. But a place like the Newman Street Tavern is not about need. It's about want. They have recently started doing brunch at weekends: brown trout Benedict, Galloway sirloin with egg and chips, green shore crab bisque and the like.

Come Fridays, some of my friends head to the country; if I need a weekend in the country I'm just going to come here.

Email Jay at jay.rayner@observer.co.uk. Follow Jay on Twitter @jayrayner1