Originally posted on 26 December 2007.
Lobsters and crabs should be purchased live and boiled at home; or, if you would rather not do your own cleaning, then they should be killed when purchased. After a tasty meal — say, your mother's birthday dinner — the shells should be saved: place in a ziplock freezer bag, and freeze until later use. For example, Christmas Eve dinner.
It is an Italian tradition, although I'm sure many other folks share it (my family is not Italian), to have seafood on Christmas Eve. Last year my family ate oyster stew; in previous years we have enjoyed eel. My family is essentially non-religious: we do most of our holiday celebrating culinarily, and Christmas Eve is a major holiday. This year, we had a bisque of lobster and crab.
Most seafood stocks start with shellfish, which are flavor-rich. Simmer covered the shells of crab and lobster with the ends of a leek (to be used the following day) and some celery for a few hours, and then strain. To the broth, add salt, some fresh meat, and cream, and serve. Seafood stocks may also be prepared with other vegetables, although the flavor should remain mild, herbs like tarragon and bay leaf, sea weeds, and other shells and fish skeletons.