Extravagantly commend a fine story (2,4,3,3)
I believe the answer is:
of mice and men
'story' is the definition.
(novel by John Steinbeck)
'extravagantly commend a fine' is the wordplay.
'extravagantly' indicates anagramming the letters (an unusual or extravagant version of the letters).
'commend'+'a'+'fine'='commendafine'
'commendafine' with letters rearranged gives 'OF MICE AND MEN'.
(Other definitions for of mice and men that I've seen before include "story by Steinbeck" , "J. Steinbeck novel" , "Dealing with people with computer devices" , "American novel" , "John Steinbeck novel" .)