Celebrating St Marcellin, maybe the world's greatest cheese But it is n o great traveller, this firm little package with the unctuous insides
It was more than 35 years ago, alas, when I first visited La Pyramide in Vienne, south of Lyon, the great restaurant where Fernand Point trained so many of today's French three-star chefs. I was in the formative years of my career as an eater, still relatively slim, as yet unacquainted with seven-course "tasting" menus and uninstructed in the catechism of gourmandise. But I was eager to learn, and Point's widow, Mado, gave me a series of lessons, leading me from trout braised in port through the famous marjolaine cake, introducing me to Condrieu and Cote Rotie, her husband's wines of choice, and pouring, to go with my coffee, a glass of crystalline eau de vie from a bottle that had somehow got a pear inside it.

The whole experience remains fixed in my memory, including the masses of orange gladioli in the corner, the biggest flower arrangement I had ever encountered, and the dogs under several tables, the first I had ever seen in a restaurant. But nothing so impressed me that day as the cheese Mme Point chose: a disk three inches in diameter and an inch thick, white with a bluish tinge. "St Marcellin," she announced. "M Point's favourite. You need nothing more."

It has been my favourite from that day to this, as much a reason for visiting the gastronomically rich area centered on Lyon as the region's celebrated restaurants - Bocuse and Blanc, Troisgros and Pic. For it is no great traveller, this firm little package with the unctuous insides. I have eaten pretty fair Roquefort in Hong Kong and more than acceptable Cheddar in the United States, to name two other candidates for the title of World's Greatest Cheese, but precious few genuine St Marcellins stray very far from their home town in east-central France. Patrick Rance, who is to cheese as Wisden is to cricket, has this to say: "What reaches most corners of the outside world is a stodgy, white, pasteurised misrepresentation of the real thing."

St Marcellin is a village of 6,500 people in the valley of the River Isere, which runs from the Alps down past Grenoble to the Rhone (and which also produces the eau de vie de poire that Mme Point used to serve). It is about 65 miles south of Lyon, a somnolent, otherwise undistinguished place that you can easily visit on a trip to the South of France, leaving the A7 motorway at Tournon and driving east for half an hour. Shops in the village, at least until recently, occasionally stocked farmhouse St Marcellins made from goat's milk or a mixture of goat's and cow's milk, as well as the cow's milk version that is now standard.

Like children, St Marcellins need a careful upbringing to show their best. That process is carried out by what the French call an affineur or, sometimes, an eleveur (literally, a teacher). When they are fresh, the three-ounce cheeses are tasty enough, but ageing in wet or dry cellars, or a combination of the two, produces a supple exterior crust and a runny, magnificently full-flavoured interior, not as strong as Maroilles, the sweaty-socks cheese, or even Livarot, the most pungent of the fine Normandy cheeses, but not bland either. The texture approximates that of Devon cream.

At its best, St Marcellin has a mild smell and a taste that builds up to bite at the end. "Il pique la langue (It stings the tongue)", I heard a happy customer cry in a Lyon bistro, not long ago. Combining experience, a watchful eye and a sensitive nose, the affineur knows precisely when to send the cheeses to market. The best St Marcellins are on sale in the summer, the products of cows' samplings of the sweet young grasses of spring. Eat one in its prime, and you will exclaim, along with the French actor Sacha Guitry, an habitue of La Pyramide in its best days: "St Marcellin, I understand now why they canonized you!"

There are plenty of good affineurs in the region, and some farther afield. Pierre Androuet, the great Paris cheese merchant, is an example, as is Phillipe Olivier of Boulogne-sur-Mer (43 rue Adolph Thiers), whose St Marcellins find their way onto the cheese boards in many good English restaurants. But the champion, without doubt, is Renee Richard, a vibrant blonde who runs a stall in the Lyon central market (La Halle, 102 cours Lafayette, a few blocks east of the Rhone). At the grand gastronomic temples of the region and most of the super-simple working-men's bouchons, you will be served St Marcellins wrapped in her trademark red-and-white paper. If pressed, even her Lyon rivals, such as the excellent Alain Martinet, whose yellow-and-black-wrapped cheeses are a little sourer and a little less sharp, acknowledge her primacy. Few people can resist her brassy, wise-cracking charm any more than her cheeses; in his book The French at Table, the American journalist Rudolph Chelminski tellingly describes her as "the Wife of Bath incarnate".

According to regional legend, the future King Louis XI, then but a young man, was out hunting one day in 1445 when he got lost and encountered a giant bear. He shouted for help, and two woodcutters came to his rescue, taking him to their cabin and feeding him bread and guess which local cheese? It was love at first bite. St Marcellin was on Louis's table in the Louvre Palace by 1461, warranted by the king, and for 500 years now it has been known as a king among cheeses