Bechamel? Impudence! (5)
I believe the answer is:
sauce
I believe this clue is a double definition.
'bechamel?' is the first definition.
(bechamel is a kind of sauce)
'impudence' is the second definition.
(thesaurus)
(Other definitions for sauce that I've seen before include "What's ... for the goose is ... for the gander" , "Cheek (sl.); ketchup" , "Dressing served with food" , "(Semi)liquid flavouring" , "Impertinence; dressing" .)