Trim the cardoons of leaves and tough ends. De-string as you would celery. Slice and blanch cardoon for approximately 15 minutes. Saute onion in butter until golden; but not brown.

In Portugal, where the cardoon is popular, several cheeses rely on the vegetable rennet, including Serra da Estrela, Azeitao and Nisa (D.O.P.), which have an earthy, tanginess to them for this reason.

I like cardoon soup, where the vegetable is puréed and strained so it's silky smooth rather than stringy. Heat equal amounts of unsalted butter and oil in a soup pot and add chopped carrot, onion ...

If you can find them in a farmers' market near you, you can braise them, or blanch them and serve them with a vinaigrette, or puree them to make soup. Blanched, they might make a lovely topping ...

Trim the cardoons of leaves and tough ends. De-string as you would celery. Slice and blanch cardoon for approximately 15 minutes. Saute onion in butter until golden; but not brown.