Mice end up cooked in sauce (9)
I believe the answer is:
impudence
'sauce' is the definition.
(I've seen this before)
'mice end up cooked' is the wordplay.
'cooked' is an anagram indicator (letters cooked into a new form).
'mice'+'end'+'up'='miceendup'
'miceendup' anagrammed gives 'IMPUDENCE'.
'in' acts as a link.
(Other definitions for impudence that I've seen before include "Audacity" , "assurance" , "Boldness and insolence" , "bad manners" , "Sauce" .)