Cook mixed arty stuffing? (9)
I believe the answer is:
taxidermy
'stuffing?' is the definition.
(stuffing dead animals)
'cook mixed arty' is the wordplay.
'cook' is an anagram indicator.
'mixed'+'arty'='mixedarty'
'mixedarty' with letters rearranged gives 'TAXIDERMY'.
(Other definitions for taxidermy that I've seen before include "The art of stuffing and mounting animal skins" , "Art of mounting the skins of animals" , "Mounting horses" , "Art of stuffing animals" , "A way to preserve wildlife?" .)