This is a really really basic thing to make, but being basic doesn’t mean that it’s not important. You probably make something like this nearly every time you cook something savory, but, did you ever think to make it in advance and freeze to quick-start your meals? We did, mainly because we have a surfeit of celery from our CSA right now, and making mirepoix is a great way to ensure that it doesn’t go to waste. The next time we start something savory — soup, beans, tomato sauce, pretty much anything — we can break out a bit of mirepoix and shave 30 minutes off our cooking time.
This is really matignon; the only difference between mirepoix and matignon is that, when you make mirepoix, you use diced vegetables, but we had so much celery we opted to use the speed of a food processor to mince the vegetables, instead of dicing them. And, full disclosure, this is thanks to Irma S. Rombauer and Marion Rombauer Becker, authors of the indispensable Joy of Cooking.
With a whole bunch of celery to use up, we made a lot of matignon; you won’t have as much.
Now, if you’re a scratcher, you might start with another trio of vegetables instead of onion, carrots, and celery. That’s fine, and it’ll work and taste great, but, technically, it’s not mirepoix or matignon. So, feel free to use onions, celery, and bell pepper (the holy trinity of Cajun cooking), or whatever you like best. We do recommend that you use unsalted butter; who’s better than you in knowing how much salt to add to your dish? If you don’t have wine — any kind you like will be perfect — a bit of water will work, instead.
Procedure in detail:
Chop vegetables. Place the onions, carrots, and celery in the bowl of a food processor and pulse until chopped to about 1/8 inch in size. We had so much we needed to do this in multiple stages, and, if we’d had less, we might have just minced it all up with a chef’s knife and used slightly bigger pieces, say, 1/4 of an inch.
Simmer. Melt the butter in a large skillet over medium-low heat. When melted, add the minced vegetables, a bit of salt, the thyme, and piece of bay leaf. Simmer until the vegetables are soft and starting to stick to the pan. You do want to simmer and keep the heat low for making mirepoix; you don’t want the vegetables to brown, just cook.
Deglaze. Once the vegetables are soft and sticking slightly, add the wine and stir, scraping up the stuck pieces from the pan. The mirepoix is done.
Pack and freeze. There are two convenient ways you can pack this up for future use. One, you can pack it into a large freezer bag and press flat, so when it freezes you’ll have a 1/2-inch-thick block. When the time comes, it’ll be easy to chop off just what you need. Or, you can do as we did, and press the mirepoix into the cups of a mini-muffin tin and freeze, transferring the pre-portioned disks to a freezer bag for longer term storage.
Remember mirepoix the next time you have a bunch of onions that are starting to go soft, or when you happen upon a great price for celery. It’ll not only use it up all and take only an hour, it’ll save you time every time you need to start a new dish, plus make your dish taste better. For that alone, five stars. And, of course, it’ll turn you into a French chef. Maybe.