It is a type of cutting vegetables into small cubes of 1 cm section, used to perfume sauces, roasts, stews and soups. The traditionally used vegetables are carrots, onions and celery but leek, turnips, peppers and mushrooms are also frequent.
It is often accompanied by a bouquet garni or spices to enhance the flavor. The Mirepoix can be white (raw) or dark (sautéed), white Mirepoix is often used for short soups, fish and seafood, you can add turnip and mushrooms, but half in proportion to the rest of ingredients.