Cardoons are the stalk-like cousins to artichokes that may also remind you of prehistoric celery. They involve no small amount of prep to make them edible, but the delicate artichoke-like flavor is worth a bit of effort. The are fairly rare creatures in the U.S. - you're most likely to find them at farmers markets, and even then they can be tricky to track down.
When and How to Buy Cardoons
Cardoons are in season in temperate areas during the cooler season from late fall often into spring. They tend to be more available around the holidays, when people with a family tradition of eating them (often Italians, but French, Spanish, and North Africans may also seek them out) look for them to re-kindle culinary connection.
Look for fresh-cut stalks. Like artichokes, cardoons brown remarkably quickly, but even though the ends of the stalks may be a bit brown even though they were harvested just the day before, you can judge the freshness by how bright the leaves are, how firm the stalks are, and how much browning is evident at the cut-end. Some browning is, as mentioned, to be expected; but it should just be a browned surface, at most, and still be fresh-looking otherwise - no decay or slime or dark browning.
How to Store Cardoons
The sooner you use cardoons, the better, but if you can't use them right away, wrap them loosely in plastic and store them in the fridge for a few days. For longer storage, peel them (see below), simmer them, drain them, wrap them tightly, and freeze them.
How to Peel Cardoons
As a relative of artichokes, it's no surprise that cardoons need a fair amount of prep before they can be eaten. Before you get started, set up a large bowl of cold water with a few tablespoons of lemon juice or vinegar added - you'll put peeled cardoon stalks there to inhibit browning once prepped.
It should be obvious to trim off the leaves and thorns. Yes, thorns. They are small, but be careful. Then peel the stalk, pulling off any larger tough strings that may show up along the way. As with artichokes, trim aggressively to make sure you end up with a tender and tasty vegetable instead of a tough mess once it's all done.
Cut the peeled stalk into whatever size pieces you want for the final product and plop them into the bowl of water you set up in the beginning.
Need more detail? See How to Clean Cardoons.
How to Blanch Cardoons
There is no doubt about it: cardoons need to be tenderized by being cooked before, oddly enough, they can be cooked. Blanch them. Put them in salted boiling water and simmer until they are tender. Depending on how big and old the cardoons were, this can take anywhere from 10 to 60 minutes. Seriously. It is crazy how big of a range there is. In general, unless you harvested them very young and brought them right into the kitchen, plan on around 30 to 40 minutes to get them tender.
Then drain them and use them in a recipe.
How to Cook Cardoons
Hands down, my favorite way to cook cardoons is to make a Cardoon Gratin. These Fried Cardoons are a close second, and I wouldn't turn down this Cream of Cardoon Soup any day of the week. If anyone wants to come over and whip up a dish of Moroccan Chicken With Cardoons, I wouldn't stop them.