I was talking, recently, to my friends the Majumdar brothers about the importance of fat. The brothers do not believe in carbohydrates which, they say, are death, but fat is a different matter. 'It's where the flavour is,' the older Majumdar said, as he ate a packet of pork scratchings. We were in the Wenlock Arms at the time, a grand old pub in that part of Islington where the postboxes are still graffitied.

At the Wenlock, they sell real ales and black-pudding sandwiches and particularly fine pork scratchings, made by Pub Originals, which have exactly the right amount of fat beneath the crackling skin. I know about these things. My wife is from the Black Country, where the scratching is an important symbol of regional identity.

The Majumdar brothers have rituals. They have so many rituals they could probably apply for a job-share as Pope. A classic Majumdar night out begins with a couple of pints and a packet of pork scratchings in the Wenlock Arms, followed by dinner at the Angel Mangal, a Turkish Ocakbasi restaurant on nearby Upper Street. Tonight, I was to be inculcated into these rituals, with an invitation to share the Angel Mangal mixed grill, during which we'd return to discussing the importance of fat.

There is a school of thought which insists that authenticity depends on location; that the best Chinese is to be found only in Chinatown, for example and that, therefore, the best Turkish restaurants are to be found only around Green Lanes in north London, in the heart of the Turkish community. Purists even insist that the mere existence of a menu marks a place out as inauthentic; that you should choose your meat from a counter. Some of the best Ocakbasis are around Green Lanes, but it does not mean they can't exist elsewhere.

The Angel Mangal does have a menu which can seem dauntingly long, with a fair list of starters at around £3, and plated dishes at £6 or £7. The simplest thing to do, though, is to turn your attention to the charcoal grill at the end of the room. The Majumdars always order the special mixed grill at £11.95, and you could do far worse than follow suit. We also ordered a few starters - fried cheese, roasted aubergine and creamed spinach, all served with great crisp flat bread (which the boys didn't eat, for carbs are death) - but they were only there to pass the time while we awaited the main event.

It arrived on a huge platter, the various meats laid on a bed of cracked wheat and rice. The Majumdars grew up in a large Bengali family where it was every child for themselves, or you went hungry. Accordingly, they now have a ritual (well, of course they do) whereby they nominate what they will eat next, so as to secure their fair share.

We started with the amana, spiced minced lamb kebabs with a serious succulence. Next came plump, salty chicken wings, then equally plump and crisp spatchcocked quail. The star turn for me, though, was the superb lamb cutlets with exactly the right amount of crispy fat. 'Without the fat,' a Majumdar said, 'it's just so much dead protein.'

We finished with 'pin rolls' of lamb breast and, finally, chunks of lamb loin. There was a big plate of salad and, being good boys, we ate some of it. The Angel Mangal is a seriously good-value night out.

And if you're worried about developing your own ribbon of fat, you could, I suppose, miss out on the pork scratchings beforehand. We will understand.

· Angel Mangal, 139 Upper Street, London N1 (020 7359 7777). Meal for two, including wine and service, £45.