What is the main ingredients for rataouille?

"A la Provençal" literally means "of the Provence" (or "from the Provence"). So, in reality most any dish can be made "a la Provençal". There are many recipes, such as "Daube Provençale", which is a stew that contains braised beef, wine, vegetables, garlic, and herbs. There is also a popular side dish called "Tomates a la Provençal", these are simply tomatoes that have been cooked in olive oil and either thickly sliced, or with the seeds scooped out, then stuffed (or topped) with breadcrumbs, herbs, and garlic. (However, it should be noted that this dish is more of an American take on their cuisine.) If you were to try to search for "a la Provençal" recipes, you would find anything from vegetables, lamb, fish, to beef, poultry, and escargot (snails).