Mirepoix is the base of many recipes, especially in soups and stews and stocks, which is a combination of onions, carrots and celery. Usually it is combined by using one part carrots, one part celery and two parts onions (or leeks), along with herbs and spices in olive oil. Because mirepoix is used in so many recipes it is easier to have it on hand and ready instead of doing the chopping and cooking every single time. A great way to accomplish this is to make one large batch of mirepoix and freeze it. Just sauté the vegetables like usual, and scoop the mixture into an ice cube tray. Let them freeze, and then put the individual cubes into a freezer bag for easy access and convenience. This is such a great way to save time while cooking!