Recast the rest in a cracking new film (7)
I believe the answer is:
western
'film' is the definition.
(Western is an example)
'recast the rest in a cracking new' is the wordplay.
'recast' indicates an anagram.
'in' indicates putting letters inside.
'a cracking' is an anagram indicator.
'rest' anagrammed gives 'ster'.
'new' is an anagram of 'wen'.
'ster' going within 'wen' is 'WESTERN'.
(Other definitions for western that I've seen before include "Old film genre, horse opera" , "Type of film or music" , "Cowboys and Indians film" , "Cowboy film of occidental origin" , "direction?" .)