Whoever discovered that the mighty palm tree has a soft and tender heart must have been desperately hungry. It's ironic, then, that heart of palm is now considered an expensive, luxurious ingredient. The vegetable is actually the core of certain types of palm tree, and the harvesting of the 'heart' kills the plant. Many of the cultivated hearts of palm on the market are taken from trees that send off multiple shoots; the hearts are taken from the shoots, rather than the main tree, which makes harvesting harmless.
Unfortunately, most of us will only taste canned hearts of palm, which, like most other canned vegetables, are pale imitations of the real thing. Fresh hearts of palm are available in places where they're grown (such as Florida, in the United States, and Brazil). Frozen hearts of palm have a gentle crispness and mild, sweet flavour, unlike the soft, insipid canned ones.
Canned hearts of palm, like canned asparagus, need assertive flavours to perk them up. Rinse the vegetables first to rid them of their tinny canned flavour. I like to serve hearts of palm with a vinaigrette made of mashed anchovies and garlic, olive oil, parsley and fresh lemon juice. Or grill the hearts of palm: cooking them this way dries them out slightly, making them firmer and concentrating the flavour.