It takes a few minutes to work out exactly what it is about the Shish that feels different.

Is it that there are so many waiters dotting about? At one point there are seven in our line of vision. Unusual, but, no, that's not it. We're talking proper, older, smiling, confident waiters here, incidentally. Not students. Our waiter actually stops us ordering a third portion of pakora and suggests instead we substitute half portions. Eh? How refreshing. It sometimes seems like everywhere else on Planet Food the staff are ordered to flog - or upsell - as much as possible.

It's not the crisp white and expensive-to-launder tablecloths either, though that's also unusual nowadays.

It's those things over there. And there. And there. Look. Men. Groups of them. Sitting at tables, eating curries, drinking beer, enjoying themselves. You simply do not see tables of male diners on a night out any more. Yet here, in the Shish, it's like the clock's been turned back to the seventies, in a good way. Some of the customers look like they've been here since the seventies, too.

We're not here on a nostalgia trip - although my mother has just leaned over and told me she thinks my uncle Peter Salvatore had his ice-cream shop on this very spot decades ago. We're here because the Shish - once hugely popular with long-haired politicians and groovy BBC types, and also once Glasgow's most famous Indian restaurant - has suddenly become globally famous.

This is because of the dish I have ordered tonight: chicken tikka masala. It was apparently - or should I say allegedly, as these things can be controversial - invented in the Shish by combining a tin of tomato soup, some cream and a chicken tikka that a customer wearing flares had thought was too dry.

Today the dish has spread around the world and no less than the Lonely Planet guide has identified Glasgow's Shish as the best place on Earth to try it. Sheesh. Before we get to that, though, we had a crisp and salty, though sweet-in-the-middle, aubergine pakora to start. We had a mixed pakora too. Clean, crisp and just what it said on the tin. There was a garlic okra poori which was sticky and unctuous and filling, and then we had the mixed grill.

Nowadays, if you order a mixed grill in a Glasgow Indian restaurant, as many Indian families do, you are presented with mountains of kebabs and grilled chicken and chops and tikkas. The Shish's version is more old school. It contains something I haven't seen since tartan stripes were de rigueur on trousers; a tandooried chicken leg. All yogurty, orangey and red, and marked with slashes and grill marks and sears from the heat. There is tikka, and a single very large tandoori prawn, some tough incinerated meat and even a shish kebab, but it's a more refined, old-fashioned take on today's dish.

A lamb saag karahi is served so full of spinach that it's almost black in its little metal dish, yet the lamb is very tender, the spices fiery and there's a general subtle sweetness to it. It also feels like there is a fair bit of ghee in there adding richness and flavour and probably calories too.

That world-famous tikka masala, then? Honestly? I was expecting something a bit redder, louder, more chemical-looking, possibly even a purple sauce. It was invented in the seventies, after all. This is all subdued pinks and creamy flashes, containing chunks of chicken and many green and surprisingly hot peppers. The overall flavour? I'm getting a sort of brandy richness, a beefy hit followed up by those chillies nipping away at the throat. The richness is something to do with the yogurt says our waiter, who is looking at me with great curiosity as I poke and peer at the bowl he has just brought.

Is this a genuine taste of the seventies, then? Possibly. If nothing else it's different.