Matricianella, Piazza San Lorenzo, Rome

It really bothers me when people keep telling me what a cushy, charmed life I lead as a restaurant critic - as if all I do is swan around eating and drinking the finest food and wine in the world.

Anyway, there I was on the Venetian lagoon, lolling about in the sunshine on the upper deck of the Missoni family yacht, sipping Prosecco and judging one of the most unusual culinary competitions in the world: the San Pellegrino Cooking Cup. Every year, 50 of the finest sailing crews team up with 50 talented Italian and international chefs for a 10-mile race during which the chefs have to concoct an original dish in the galley below deck. Many of the entries hailed from the weird, wild and wacky world of nuova cucina, with its raw fish, rampant foams, blue risottos, ravioli skins fashioned out of raw scampi, and, memorably, lobster served on a bed of broccoli, pineapple and strawberries.

Helping me make sense of this crash course in modern Italian cookery, was fellow judge Emanuele Scarello, the talented Michelin-starred chef of Udine's Agli Amici and creator of a futuristic flourless pasta made only from egg. Between dishes, I picked his brains on what's hot in Rome, wishing to catch up on the latest trends in the eternal city.

"In Roma," he replied, "I go to Matricianella".

Good grief. I have walked past Matricianella a dozen times and dismissed it as a tourist tratt; just one more checked-tablecloth, creamy-pasta, sweaty-wine den with up-you prices. Now here I am, actually walking in.

Located just around the corner from the Piazza San Lorenzo (a good spot for an aperitif), this is your typical Lady and the Tramp trattoria, with its pretty outdoor tables, and three softly glowing ochre dining rooms decked out with blue and white checked clothed tables, wicker-seated chairs, copper pots and fading newspaper reviews. But the décor I like best is the leg of prosciutto San Daniele perched on a carving stand, and a refrigerated cabinet full of cheese and fruit.

The first room is populated with noisy Italian families and couples; the second a mixture of Italians and stranieri (foreigners); while the third is an English-speaking tourist enclave. After grovelling to my host, an ample-girthed, operatic character with glossy long black hair and half-moon spectacles, I get a table in the first room.

Signore Operatico places an enormous book on my table, with a heavy thud. It is the wine list, a good 8cm thick, with entries for the great Tignanello and Sassicaia as well as the more everyday Italians. The prices are outrageously, farcically, how-can-they-do-this low. A nicely built, ripe, spicy Pio Cesare Nebbiolo d'Alba is a steal at £13.50 (I could go through life drinking nothing but Pio Cesare wines), while a fresh, lightly floral, Ceretto Blange Arneis is £10.50 - the same price it goes for at Fiumicino airport.

The menu is utterly, totally, Roman, running from trippa alla romana (tripe with tomato, mint and pecorino) to Roman-style meatballs, and scottaditto ("burn your fingers" grilled lamb chops). The locals all start with fritti; little deep-fried morsels of courgette flowers, artichoke, fish, meat, and anything that will stay still long enough to be battered.

Desperate for pasta, I cannot resist a generous serving of rigatoni con pajata (£5.50), ridged pasta the size of bicycle inner tubes in a rich, tomatoey sauce studded with tender, milky strips of calves' intestines. This is a texturally magical dish. Also on the table is a classic spaghetti alla carbonara (£5.50); rich, eggy, staunchly al dente and littered with chunks of peppery guanciale (cured pork cheek).

It is not just the wines that are knock-me-dead bargain-priced. A smoky, hot-off-the-coals seafood grill of four impeccably fresh scampi (langoustines) and two good-sized calamari is just £8.

Abbacchio al forno (£9) is the roast lamb of my dreams; two good chunks of baby suckling lamb, surrounded by golden, lamb-imbued roast potatoes. I am in heaven. The meat is fall-apart, fragrant with herbs and jammed with flavour. On the side, spinach flavoured with balsamic vinegar and sultanas (£4), and intense, wilted cicoria di campo (dandelion, £3) are more than mere bit players.

Pud comes from the fridge - a bowl of perfumed, seedy, heady fragoline di bosco or wild strawberries (£5) with a scoop of gelato di crema.

If you want to know where Roman food is going, Matricianella is not going to tell you. For that, you need to go to Crudo, L'Altro Mastai, Il Pagliaccio, Don Alfonso's Baby and the three-star La Pergola. But if you want to know where it's been, come here for a true celebration of traditional Roman cooking. So many other Roman trattorie - Mario, Nino, Othello - have been run into the ground, but the Lo Bianco family has kept this 60-year-old fresh and alive, strengthened rather than diminished by age. The service is bustling, the plates are crowded, the flavours are gutsy, the place is packed, and the value is unbelievable. Now tell me I don't earn my keep.

16/20

Scores 1-9 stay home and cook 10-11 needs help 12 OK 13 pleasant enough 14 good 15 very good 16 capable of greatness 17 special, can't wait to go back 18 highly honourable 19 unique and memorable 20 as good as it gets

Second helpings: More eternal Roman favourites

Checchino dal 1887 Via di Monte Testaccio, 30, tel: 00 39 06 574 3816 Through five generations, Checchino has been turning the unmentionable bits of pigs, sheep and cows into a noble feast. This most Roman of restaurants is the birthplace of the famous coda alla vaccinara (oxtail stew).

Tullio Via San Nicola da Tolentino, 26, tel: 00 39 06 474 5560 Since 1950, Tullio has been a hotbed of Florentine hospitality in the middle of the Rome. Try the famous grilled Tuscan steak, matched to a fine Tuscan red.

Rosetta Via della Rosetta, 8/9, tel: 00 39 06 686 1002 For more than 40 years, the Riccioli family has been serving up some of Rome's finest seafood just a stone's throw from the Pantheon. Pricey, but classy.