"What's cooking?" It's an American expression, used as the equivalent of "What's going on?" I'm guessing that its popularity peaked in the middle of the 20th century. One of the more modern replacements is "What's up?" or in a more specialized jargon, "Whazzup?" The OED cites examples from the 1940s and '50s, and offers, as one gloss, "What's in train?" The question meant literally is still viable, often said when the husband or someone else wanders into the kitchen to track the source of some desirable aroma, or just to inquire as to what's for dinner. "What's cookin', good lookin'?" could be said (1940s and later) to a cook, but was more often just something to say to a pretty girl, sometimes as a potential conversation opener, or just a signal of interest. For our purposes this is more the traditional meaning of what is it you are making for dinner or lunch. we have