I didn’t know what to make of it. In London back then—and still, too often, now—pastrami was a blunt hit of fire and spice, the beef brisket sliced so wafer thin that it fractured and crumbled if you tried to pick it up with your fingers. It was dry. This, however, was a monster, filled with thick slices of beef, the deep rosy pink of the best satin knickers. Yes, the meat was spiced, but it was also soft and moist and smoky. It was the best sandwich I had ever eaten.

It was also a source of a major cultural dislocation. I have a long been a godless Jew, one who worshipped at his late mother’s non-kosher fridge. My expectation was that in New York I could understand my cultural Jewishness through foods that were familiar to me; while I did not have religious ritual by which to define myself, I could do so through lunch.

The problem was that lunch just wasn't so familiar. In London, bagels—pronounced bye-gels (and spelt beigels) if your family still recalled its beginnings in the capital's East End—were small and dense. In New York they were huge pillowy things. In London in the early 90s almost all salt beef I came across was thin cut, and served on sugary white bread spread with a smear of nose-tickling English mustard. In New York, it was thick cut, fat optional, and served on a dense rye bread that let you know you'd eaten it.

But there was something else. In London this food was a kind of exotica. It was for what my mother laughingly referred to as the 'k'nossers' (fake Yiddish for 'connoisseur'). A taste for these foods, for the very stuff of necessity – who else would brine their beef than those with no way of keeping it fresh? – marked us as different from our Christian brethren. We might be middle-class and settled now, but once we had been immigrants, and before that we had been on the run from the Cossacks across the Russian Steppes. Hence we salted our beef. In America these dishes were part of the culinary vernacular. It seemed every town and city had its deli with dishes which, whether kosher or not, drew on Jewish traditions. What I thought of as the food of the Ashkenazi Jews of Eastern Europe was here just food. It was everywhere and everything. I was jealous as hell.

In 1997 when I came to write a novel about Anglo-Jewry it made sense to me that food should be front and centre. In truth if food hadn’t been there, it would have been no book at all. Day of Atonement, finally published in eBook and now available in the United States for the very first time, is about two boys who meet down the side of a synagogue for a cigarette break during the Rosh Hashanah service. One has invented a machine for taking the schmaltz off chicken soup quickly, without waiting for it to cool. The other has the smarts to turn it into a business. Together they found a world-beating restaurant and hotel empire, until it all comes crashing down in a mess of insider trading and drug abuse.

As the shout line on the original cover said, it’s about power, ambition, and chicken soup. And salt beef. And pickles. And gefilte fish. And bagels. It’s about two men who communicate through food and sell their own appetites to others. As part of that story these two North London Jews bring New York-style delis to London. They recognise that British Jewish food is not the same as American Jewish food and that the shock of the unknown might give them a market advantage.

It’s a curious aspect of immigrant life. Communities may seem the same, may have cultural or religious identifiers in common, but their tastes and habits can be profoundly altered by where they evolve. For example, Cantonese food in America is different to Cantonese food in Britain. (It’s sweeter). And Jewish food in New York is very different to that in London.

Or at least it once was. In the 18 years since I first published my novel about Jews and food, the world has contracted. The Atlantic has shrunk, and food trends have travelled from one side of the world to the other with ease. Now in London you can get terrific salt beef, served thick-cut on hefty rye bread. And you can get real pastrami, in the New York style, not just the flaky stuff that crumbles unto dust.

We are meant to be protective of our own culinary traditions. We are meant to bemoan the way tastes from elsewhere overwhelm our own ways of doing things. But in this case I’ll make an exception. As far as I’m concerned the availability in London of a proper New York-style pastrami sandwich is the very definition of progress.

Jay Rayner's Day of Atonement is available from Amazon.com as a Kindle Special. It will be free to download on September 14 and 15 (Rosh Hashanah) and will cost $3.99 thereafter.