Mirepoix

Mirepoix is a mix of chopped onion, carrot and celery, the flavor base of much French cooking. The classic ratio is 2 parts onion, 1 part carrot and 1 part celery by weight. It is cooked in fat at the start of soups, sauces and braises, or simmered whole in stock. Most people never taste it on its own, but they notice when it is missing.

How to do it

1. Weigh out 2 parts onion to 1 part carrot and 1 part celery. For a pot of soup, 200 g onion, 100 g carrot and 100 g celery is a good start, roughly 1 large onion, 1 large carrot and 2 stalks of celery.
2. Cut them to suit the cooking time. Dice them small, about 5 mm (1/4 inch), for sauces and quick soups, and leave them in large chunks for stocks that simmer for hours.
3. For most soups and sauces, sweat the mirepoix in butter or oil over medium-low heat for 8 to 10 minutes until soft but not brown.
4. For brown stocks and dark stews, cook it over higher heat or roast it until golden.

How to use it

Mirepoix starts stews, braises, risotto, lentil soup, bolognese and pot roast. It flavors stocks, and it is roasted under meat as a bed that later flavors the gravy. A white mirepoix uses leek, parsnip or mushrooms instead of carrot to keep a pale sauce white.

How to store it

Diced mirepoix keeps in a covered container in the fridge for 3 to 4 days, or in the freezer for up to 3 months.

Common mistakes

• Cutting pieces in very different sizes, so they cook unevenly.
• Rushing it over high heat when the recipe asks for soft, sweet vegetables.
• Cutting it tiny for a long stock, which turns it to mush and clouds the liquid.

Where it comes from

The name is said to come from the Duke of Lévis-Mirepoix, an 18th-century French noble, whose cook is credited with it. Other cuisines have their own versions: the holy trinity in Louisiana, soffritto in Italy and sofrito in Spain and Latin America.