A walk through Machane Yehuda will reveal these enormously long celery-like vegetables on display at vendors throughout the market. A closer inspection reveals spike-like growths along the edge of the ribs, but they’re actually leaf buds. They leaves themselves look somewhat jagged.
Cardoons are relatives of artichokes, members of the thistle family. They’re also relatives of the milk thistle, which is that really tough weed you get in your Israeli lawn; it’s the one with the white-veined leaves with the sharp thorns on the edges. Cardoons supply a necessary enzyme for vegetable rennet, and there are cheeses made using this form of rennet. Slow down, caseophiles; it’s found in the stamens, which are already cut off before they reach market, not the stalks. You didn’t think it would be that easy, did you?
Like an artichoke (and I imagine other non-edible thistles), cardoons can’t be eaten raw, owing to a horrendous bitter aftertaste. Most recipes call for boiling the cardoons in water with the juice of 1/2 a lemon. Good advice. Their subtle flavor once cooked can be easily overwhelmed by stronger flavors, so if you’re going to try this, it would be best to star in its own dish frittered, roasted, sauteed, braised or in a soup, with a minimum of competing flavors.