Athens 2004 is almost upon us, and for one supermarket, the race is on to find the perfect moussaka recipe. Caroline Stacey reports from Crete

Here are more remote parts of Crete. Even so, as tourists shuttle between Chania airport on the Akrotiri peninsula to the harbour town and west to the beaches, Mrs Antonia's bar and taverna is not on anyone's route. Not unless they know what they're looking for.

Here are more remote parts of Crete. Even so, as tourists shuttle between Chania airport on the Akrotiri peninsula to the harbour town and west to the beaches, Mrs Antonia's bar and taverna is not on anyone's route. Not unless they know what they're looking for.

What they would find is reputedly one of the best lunches in Crete. And Crete isn't just a cradle of civilisation and mythology, it's an island of plenty, with the healthiest diet and the longest life expectancy in the Med. It all contributes to a reputation for the best food and cooking in Greece. The goat's and sheep's cheeses pre-date Minoan civilisation. It is abundant with olive and citrus groves, honey, apples, walnuts, vegetables, grains and herbs.

As usual, Mrs Antonia has shopped in the market, brought her bags back on the bus, and plonked them down on a battered kitchen table alongside an unclaimed packet of Peter Stuyvesant. Her hob is blazing; steam comes from a soot-caked pan on a fire of gnarled logs. She's been working since 7am, cooking for a handful of locals. In the past she attracted Nato personnel from the now-abandoned base at Souda. Today she's preparing for a party of English visitors who have singled out her cooking as the gold standard of Greek food.

The Marks & Spencer team, product developer Janine Wills and food technologist Akis Stylianou, are retracing a journey they've already made twice before, to find the unlikely-looking source of this summer's must-buy Greek dishes. It's only part of a huge collection of Mediterranean meals, but because of the interest generated by the Olympics in Athens, they've been especially assiduous in their research into Greek food. Now the company's gastronauts have returned to the village of Pazinos to remind themselves how their moussaka should taste, hoping that the recipe they extracted from Mrs Antonia is being accurately reproduced in the British factory.

Mrs Antonia is single-handedly pulling together a lunch of moussaka, boureki (meltingly soft courgettes and waxy potatoes baked with misithra, a ricotta-like curd cheese, feta and mint) meatballs and youvetsi (lamb cooked with orzo pasta the size of grains of rice). Her hands blackened with newsprint and soot, she scurries between her kitchen and the oven down the lane in an outhouse.

Using a folded newspaper as an ovenglove, she pulls out the first battered pan of moussaka, the golden, soufflé'd top only slightly flecked with ash. Then she makes her chips (hands still blackened by the newsprint) on an ancient mandolin clogged with potato starch. She blanches, salts and fries them twice in olive oil. Mrs Antonia doesn't take shortcuts.

It goes without saying that she doesn't weigh or measure anything. Wills, the brains behind many of M&S's Mediterranean meals, stood over her as she cooked, taking notes. The moussaka starts with an oiled dish, then a layer of potatoes. She fries the aubergines, then salts and sugars them afterwards. Onion, meat and a minimum of tomatoes are cooked for 45 minutes before she assembles it all and adds a bechamel sauce thickened with vast amounts of Graviera sheep's cheese. Determined to replicate it as closely as possible, M&S is using the same Graviera from the biggest dairy in Crete, and Cyprus potatoes. They're even selling it in an earthenware dish.

Mrs Antonia's smooth meatballs impressed them so much, they've included her surprise and no-longer-secret ingredient: Carnation milk. What they can't do is cook their dishes in a wood-fired oven - none of the factories has one - but still want them to taste as if they have been. "Intense heat for several hours gives the intensity of flavour," explains Stylianou. So they have to cook the tomato sauces longer to concentrate the flavour, though it costs more as the weight of ingredients needed is greater. And getting the right recipe is only the beginning of the process.

Wills and Stylianou have travelled to the South of France, Spain and Portugal, searching for the original versions of dishes that offer shoppers the essence of the Mediterranean. What follows are long days in the factory, negotiating with the chefs, working with the ingredients, within the budgets and the manufacturing technology, towards a mass-produced version that captures the taste that first knocked them out in Athens or Aix en Provence. In the village of Vamos, more picturesque than Pazinos, chef Christos Lassados' restaurant Sterna Bloumosifis, puts on a spread that bears no relation to the idea most of us have of Greek food. There's a broad-bean dip, stuffed aubergines, octopus, green salad of the bitter wild greens called stamnagathi, horta, the generic word for wild green leaves (dandelion is the closest) that are eaten boiled or wilted with lemon dressing or raw, lamb and pork from the wood oven. Aubergine is baked with walnuts, misithra, tomato, mint and parsley. Finally there's quince and Greek yoghurt.

They came back from Greece with 18 potential dishes, but have to weigh up their enthusiasm against what will sell. Customers are only prepared to experiment so far. "We've eaten some fantastic octopus," says Wills. "But can we get away with it at home?"

Shrimp saganaki, borrowed from Christos, did make the shortlist. Plump prawns in an intense tomato sauce with cheese on top, is an exceptional and unusual combination. They're using Graviera for this too. Here all we know is feta, but the Greeks are Europe's biggest cheese eaters; they get through an alleged 25 kilos each a year, mostly of feta, but cheeses like misithra, and the buttery staka, a soft goat's cheese, are produced in Crete.

"Holidaymakers would never go to the places we're going to," says Stylianou, as we head east to the furthest edge of Chania's old harbour to Chrisostomos' eponymous restaurant. It's not far from the fast-food joints advertising "chicken nuckets (snitsel)" but a world away from the tourists' image of Greek food. Wholegrain pain de campagne is baked in the wood-fired oven on the first floor. A leg of lamb comes out of the inferno glistening and burnished, surrounded by huge potatoes. This is kleftiko, which translates as "stolen". Although Cretans weren't much bothered by who owned which sheep, if they feared being accused of theft they cooked them in underground pits to avoid detection.

Chania's clubbers congregate at dawn to eat restorative tripe soup from a stall at the market; others wait a little longer for a second breakfast of souvlaki, the generic name for a kebab. At the unprepossessing Oasis souvlaki bar in downtown Chania, hungry labourers are shovelling down the best souvlaki in town. This giros - like a doner kebab - consists of grilled meat and the freshest bread. The proprietor brushes the pitta with oil, wraps the meat in the bread, adds tomato and yoghurt and, with a practised flourish, sprinkles oregano and paprika. Wills is on her second breakfast, and is ecstatic. She wants the souvlaki she's developed to be as much like this as possible. Fluffy flatbread, and pork marinaded in oregano, lemon juice and olive oil then fried, plus a pot of Greek yoghurt are sold ready to assemble at home. Will punters be prepared to brush the bread with oil, warm it and put the kebab together to eat while they watch the athletics in Athens?

Wills and Stylianou tried everything they could to get an impression of the best Greece could offer. They've eaten fusion Greek food (lobster croquettes with soya, lime and mint sauce) to a Sting soundtrack in Aristera-Dexia, the trendiest joint in Athens. And souvlaki in Mitropoleos, a side street in the Plaka, against a more typical backbeat of pneumatic drills - the build-up to the Olympics has made the city even noisier. "Anybody can go and eat delicious food on a trip. Getting chefs to make it as good as you want it, in a factory, in huge quantities, conveying exactly how you want it to taste - that's the challenge," says Wills.

If it seems strange that the people from a British retailer should have gone to such trouble to discover the real Greek food, they're making an investment. Ready meals are a part of the fashion industry. Even if certain gastronomic lines only run for six months - they're seasonal, too - getting it right repays the research.

Factories in Wales, Scotland and England are making the Greek meals to Wills' and Stylianou's specifications. The boureki, prawn saganaki, meatballs, and youvetsi really are as close as you can get to the real thing. And a factory in East Anglia is now producing 10,000 moussakas a week that bear a remarkable similarity to Mrs Antonia's.