And here I thought this was some piece of gossip that, when it gets passed around, people know right away who started it. "You're telling me you heard he's acing the class because he's doing the professor? Oh, I know who's telling those tales. That dish has Miss Sour Grapes' name written all over it!"
But that implies one has only one thing that one cooks a lot and shares with others, as most people have only one (pretty distinctive) signature. What do you call it if you cook a few different dishes a lot?