PARIS, July 29, 2007 (AFP) - The title of Pixar's latest animated film Ratatouille loosely translates as "a mish-mash of vegetables." That doesn't stop people in southern France, particularly Nice where the dish originated, from having vehement opinions about how it should be prepared.

Classic books on Provencal and Nicois cooking agree on the vegetables that should go into ratatouille: tomato, onion, bell pepper, aubergine and courgette, with the occasional recipe calling for a little potato.

It goes without saying that these vegetables should be ultra-fresh and seasonal, which means ratatouille is very much a summer dish.

Recipes invariably call for large quantities of each vegetable, as leftovers are desirable. Beyond that, the proportions, cooking times and techniques can vary wildly.

The French cooking encyclopedia Larousse Gastronomique points out that ratatouille, which comes from the French word "touiller" (to stir), was "once designated an unappetizing stew." It provides a rustic recipe for this dish in which only the aubergine is cooked separately in olive oil before all the vegetables are added to the pot.

Other recipes don't let the cook off so easily.

In the book "Provence-Alpes-Cotes d'Azur: produits du terroir et recettes traditionnelles", part of a carefully researched culinary heritage series published by Albin Michel, the tomatoes simmer for an hour with olive oil, garlic and herbs, while the onions slowly caramelize in a separate pan and the aubergines, courgettes and peppers are sauteed one by one. In this version the tomatoes outweigh all the other vegetables combined.

The late Jacques Medecin, a notorious (and food-loving) former mayor of Nice, gave a variation with 1.5 kg (2.2 pounds) of tomatoes to 1 kg each of the other vegetables in "Cuisine Niçoise: Recipes from a Mediterrranean Kitchen" (Grub Street). Each vegetable is cooked separately before being combined in the same pot, as in the recipe above.

"Too often," wrote Medecin with the precision he showed for cooking if not politics, "we content ourselves with a preparation in which the proportions do not reflect the science that our ancestors passed down to us. Or the dish is overcooked, badly cooked, undercooked, creating a ratatouille that is pasty, or not homogenous, or with too much of a bite."

Helene Barale, whose restaurant near the Nice port was legendary for its home-style cooking until her death in 2005, used a smaller quantity of tomatoes and roasted the bell peppers to remove their skins before frying them for five minutes (separately, of course).

At the 20-seat Nicois bistro La Merenda, run by former Hotel Negresco chef Dominic Le Stanc, a classic chunky ratatouille is served cold to better appreciate the individual flavours of the vegetables. Most recipes say the vegetables should be cut into rounds, though they may also be cut into cubes or strips.

Franck Cerutti, who grew up on a farm in the mountains behind Nice before becoming chef at the three-Michelin-star restaurant Le Louis XV in Monaco, has made ratatouille many different ways in his years as a chef on the French Riviera.

"Ratatouille is a dish that every Nicois makes," he says. "They might not make their own pasta because they can buy it fresh, but they know how to make ratatouille. You can eat it hot, warm or cold, but I think it's best at room temperature. I also love to reheat it and poach eggs in the mixture."

While working for famed Provencal chef Jacques Maximin, who now runs La Table des Amis in Vence, he made a "confit-style" ratatouille in which the vegetables were cut into very small cubes and added to the same pot one by one (first the peppers, then the aubergines, courgettes and tomatoes) before being cooked on low heat for an hour.

He approves of the traditional method that involves cooking the vegetables separately, but says each vegetable should be drained of its oil to avoid a finished dish that's drowning in fat. "When it's cooked all th