I haven't written about blood in this column only because, like lungs from last week, it is so difficult to track down fresh poultry blood or find a restaurant that knows how to handle it. (Which is to say, to not handle it very much at all: There is nothing worse than overcooked blood; it becomes leathery and its delicate, intangible flavor dries up as well.) Prepared properly, congealed blood really is one of my favorite flavors. More