Every part of the Mediterranean has its talismanic fish dish. The rascasse bouillabaisse of the south of France, the tuna of southern Italy, octopus of Greece, the great oily mixed fried fish of Spain. In Algiers, it’s sardines, the most ubiquitous of shoals. Back home, they’re relegated to the metaphor of a crammed tin, a lonely man’s supper, but here, on the hot south coast, sardines come in great glittering migration. In Algiers, they are everywhere — beloved and cheap, elegant and honest. The flavour of a freshly grilled sardine is as good as anything that comes out of the sea, and the citizens never tire of them.

You can forget, or fail to remember, that Algiers is on the Mediterranean. From our side, the north side, it looks like such a European holiday sea, but Algeria owns its longest stretch of coast, and is just across the water from the Balearics and the coast of Spain. The city obliquely stares at Marseilles, which, in so many respects — cultural and historic — is its sister port.

Not many people visit Algiers these days. The country is coming out of a particularly dark and murderous civil war and seems to be suffering from a collective post-traumatic stress disorder. It hadn’t welcomed Europeans for some time. We were with Mourad Mazouz, owner of Momo and Sketch and the spectacular Parisian restaurant Derrière. This is his city, and it was once packed with travellers and Europeans. The ferries pass back and forth in the busy port. It is one of the most beautiful places on the Mediterranean, built on a huge bay, with white French colonial colonnades with blue windows and shutters on the boulevards in front of the ottoman casbah, crumbling and feral.

Because there aren’t that many tourists, there aren’t that many tourist restaurants, but there are cafes.Hundreds of them. Algiers got the benefit of being colonised by two great cafe societies, the Turks and the French. Men sit and argue volubly at little tables, play slam-dunk dominoes and greasily slapped cards, and smoke as if it were an endurance sport. As with all cities that tend to live as large families, the best food is eaten at home. Algerian cuisine is particularly polyglot, a stew of Berber, Arab, Jewish, French and southern Spanish. The Algerian fleet sailed round the world as pirates and traders. It is through north Africa that Europe got many of its ingredients: sugar cane and spices and roses and lemons and oranges.

The Algiers fish market is dark and cacophonous and slippery, a warren of traders, of ice boys, of bandy lads pushing trolleys, balancing baskets; the mongers sit cross-legged, like henna-stained Neptunes, surrounded by their silvery wealth. It is difficult to think that all this came from the same waters as the neat goods in the refined and epicurean markets of Nice.

One of the great surprises here were the desert truffles, a distant relative of the French and Italian ones. These are Arab delicacies that are exported to the markets of Riyadh and the Gulf. They are grown in arid, sparse soil and collected by the Berbers, who look for the telltale cracks in the earth. They say that the truffles grow where lightning has struck, an electric gift from the heavens. If there are a lot of storms, with the spring rain, then there will be a good crop of truffles. They’re brown, the size of small potatoes, and have a strange, distinguished but fugitive flavour. It is dusty, secret, like the smell of a gardener’s pocket. We eat them, cooked in rancid butter, with a stew of lamb that has been hung so high and so long, its flavour ululates. The combination of these competing, turning methods on the truffle is extraordinarily broad and emphatic. Deep, sour, carnal and mordant, it is absolutely the taste of the place. This dish wouldn’t travel, no restaurant in Europe would serve it, but here, in the warm night, it is intimate and sensual. And deliciously authentic. After it, I'm offered small apples stuffed with almonds and stewed with mutton bones, again a mouthful that is consistently discordant, uncompromising and foreign, but also beguiling. We have sherbet of lemon, mint and orange-flower water, and a perfect comforting bread made of spelt.

The great pleasure of dinner here is that you can’t just chew and forget. This is not easy eating. Nothing is bland or edited, and it is a reminder of how much of our food is. Here, you need to concentrate; there’s nothing passive about dinner. You need to wrestle what’s in your mouth, come to terms with it, take your time. And you need to concentrate on who’s sitting next to you. We never had a meal that didn’t come with an argument. Algerians talk with purpose and varying degrees of force. The opinions are like the mutton, high and gamey. They thump the table, wag fingers, roll their eyes and make gasping, sighing, plosive noises, like car horns, to underline infuriation or ridicule, or just move the argument along. Everybody is bloody furious all the time; it’s invigorating.

The best meal was dinner at Mourad’s family home. A white couscous, with mutton and chicken and turnips and carrots. My grains were given just the right amount of stock by Mourad’s father, who explained with signs that the dish must be eaten not too dry and not too soupy in the way you might explain to an idiot how to do up his shoelaces. After the sweet cake and mint tea, the men take oranges and peel them with strong craftsmen’s fingers. Without drawing breath they pass the segments to small children, clouting the backs of little heads with affection. The dining room is full of the scent of citrus and mint and the fog of guttural voices putting the badly mistaken to rights.

Momo, 25 Heddon Street, W1; 020 7434 4040, momoresto.com

Times Recommends

• Top Ten most searched for recipes
• Chalet Chef 2010: the winning menus
• Gin and pomegranate jellies