Who could be the inventor of this extraordinary gelato al baccala? And what on earth did it taste like? A chase was soon on, leading, as it turned out, to the door of Matteo Napoli, ice-cream maker extraordinaire whose shop in an unassuming suburb of Salerno has a dedicated local following but is little known to the rest of Italy.
The salt cod is perhaps the least of the surprises awaiting the unsuspecting visitor. "I've been making that one since 1962," Matteo - as he insists on being called by one and all - said nonchalantly. "Why don't you look at the other things on offer?"
The other things include rocket ice-cream, popcorn ice-cream, ice-cream with seafood risotto, salmon ice-cream, celery ice-cream, fennel ice-cream, even ice-cream flavoured with short pasta and Borlotti beans. And that is not to mention the other 100-odd, more orthodox flavours, from chestnut to pomegranate to lemon, strawberry and chocolate, that Matteo Napoli has been working on in his 54-year career.
One might be tempted to write off Matteo as a bit of a show-off, someone who is merely amused at the idea of putting preposterous ingredients into the humble ice-cream. But that would be quite wrong.
His aim is nothing less and nothing more than to watch his customers' faces break out into irrepressible smiles as they bite into his creations. For his ice-creams are not only unusual, they also taste fantastic. The savoury confections take a bit of getting used to, but they are beautifully blended to win over the most sceptical of tasters.
"I don't have any secrets. My only trick is to use only the freshest natural ingredients with no artificial additives at all," Matteo said as he began a mouth-watering tour of his cavernous, brightly lit shop and even larger kitchen, known as his "laboratory".
It soon became apparent that this is a very special place indeed. The curled, serrated knives that Matteo's assistants use to gouge the fruit out of hundreds of peaches have been custom-made for him. The whisker- emulsifier machines that turn the raw ingredients into ice-cream have been developed for Matteo by a specialist firm in Bergamo in the north.
For Matteo does not just make very good ice-cream. He is responsible for some of the key technical breakthroughs in his field over the past three decades. Aside from the unusual flavours, he is famous for stuffing fruit and vegetables with ice-cream made from the flesh inside. Perhaps his most important contribution was to pasteurise at least part of the sugar he used. By heating the sugar to 85C, squirting it with freshly squeezed lemon juice and then, when it has cooled, adding bicarbonate of soda, he creates a sweetness close to that of fructose that ensures a marvellous lightness and delicacy.
If Matteo is not better known, it is largely because he does not want to lose personal control of the creative process and see his business turn into a mini-industry forced to compromise on quality. Early in his career, when he first set up his own shop in Naples, he turned down the opportunity to supply one of the biggest bars in central Salerno, even though it was run by a friend of his. More recently, a British buyer asked him to supply an astonishing 900,000kg per week.
"Of course I said no," said Matteo. "Either you do something properly or you don't do it at all. The great ills of the world are caused by money - money, sex and religion. I prefer to keep things the way they are." So he remains the proud monarch of his little kingdom in the depressed Salerno hinterland, delighting his dedicated followers, and not worrying too much about status. Every now and again he caters for a wedding in Hawaii or Boston, or flies to Brazil to run a training course, but these are the exception rather than the rule.
His wife, Raffaelina, minds the till and the financial end of the business. Their son had ambitions to expand to Rome and beyond, but he died in an accident last year and the family has since closed ranks.
Matteo's latest invention is very much a family one: il gelato bebe Alessandro, a confection specially made for his infant grandson. It is made of sponge-fingers, honey and milk and, to judge by the reaction of one nine-month-old, could turn even the most recalcitrant child into a die-hard ice-cream fan.