But wait! There's more! Another quote from an NPR station's cooking show recipe page (I know, grammar geeks, that's like a compound modifier from hell):

Daniel says: "When I was growing up in New York, every Chinese restaurant served duck sauce and hot mustard.  I have no idea where duck sauce came from originally, but I've always missed it since moving to California.  The above recipe is my attempt to reconstruct the flavor of the sauce.  I'd always mix in as much hot mustard as I could stand and use it as a dip for the fried egg noodles that came with soups."

Daniel, go out & buy some plum sauce!