Onions, carrots and celery are a trio of ingredients that can really get you cooking. The combination of veggies is called mirepoix (meer-pwah) in some culinary circles and it's the trifecta of ingredients for stocks, soups, sauces and many other things.
To create mirepoix, all you'll need is the vegetables and a sharp chef's knife or santoku knife to do the chopping. The more uniform the pieces, the more evenly they'll cook, and the smaller the pieces, the more quickly the flavors will be released into a stock.
To chop the onions, cut the onion in half stem to root. Remove the skin, lay one onion half flat on the cutting board and cut off the stem, leaving the root intact. Make a series of horizontal cuts starting toward the bottom of the onion, working your way up.
Then, make vertical cuts using the tip of your knife, keeping in mind the size of the dice you hope to achieve.
Slice through the patchwork of cuts to create a uniform dice.
Here's a video that might help.
For the carrots, you can choose to leave the peel on or remove it. Either way will work to make vegetable stock. If you leave the peel on, be sure to scrub the carrots before dicing. When dicing celery, you can include the leaves since the vegetables will eventually be strained out.
What's great about mirepoix is that you can do all of your chopping ahead of time and freeze the vegetable mixture to use, as needed.
Chef Susan Goss of Kitchen Witch Consulting says that since flavor is the most important factor, not texture, freezing works.
“You usually cook mirepoix until its soft anyway so as long as the fresh flavor of the vegetable is not compromised, I think freezing would be okay,” she said.
Here's Chef Goss' recipe for Vegetable Stock. Re-printed with permission from West Town Tavern: Contemporary Comfort Food by Susan Goss with Drew Goss. 2010.
Unlike the meat retained from meat stocks, the vegetables have pretty much given all they have to the stock and should be discarded or composted.
White and cremini mushrooms do not have enough flavor to stand in for the shiitakes. However, a delicious stock may be made with 12 ounces of white or cremini mushrooms and 1/2 ounce of dried porcini mushrooms. Soak the dried porcinis in 2 cups of hot water for 30 minutes before using. Lift the porcinis out of the soaking liquid and add to the stock ingredients. Strain the porcini liquid through a piece of cheese cloth to catch any grit and use it as part of the 3 quarts of water called for in the recipe.
Chef Goss' Vegetable Stock
- 2 pounds Roma tomatoes, about 8 large
- 1/2 teaspoon kosher salt
- 1/4 teaspoon ground black pepper
- 1 sprig rosemary
- 6 sprigs thyme
- 1 large onion, about 8 ounces, peeled and chopped
- 3/4 pound shiitake mushrooms with stems, halved, about 2 quarts
- 1/2 pound carrots, scrubbed, unpeeled, chopped
- 4 large outer celery ribs with leaves, chopped, about 1/2 pound
- 1/4 teaspoon whole coriander seed
- 6 juniper berries
- 1/4 teaspoon whole white peppercorns
- 2 large bay leaves
- 6 sprigs parsley, or parsley stems
- 1/2 cup dry white wine, optional
- In a 6 quart stockpot over medium heat, cook the tomatoes until they release their juices. Add the salt, black pepper, rosemary and thyme and stir well. Cook until herbs are fragrant, about 2 minutes.
- Add the remaining ingredients as well as 3 quarts of cold water.
- Turn heat to high and bring the water to a boil. Adjust heat so water “smiles” and cover the stockpot tightly with a lid or foil. Let stock simmer for 45 minutes, checking every 15 minutes or so and adjusting heat so stock simmers slowly. You want to steep the vegetables slowly in the water to extract all the flavors.
- Remove the stock from the heat and chill the stock with the vegetables using an ice bath. Position a sturdy colander over a large bowl or another stockpot. When stock is room temperature strain it through the colander into the bowl. Use a ladle or wooden spoon to press on the vegetables and extract as much liquid as possible.