Cook a sort of stew (5)
I believe the answer is:
roast
'cook' is the definition.
(I know that cook is the is a more specific form of the action of roast.)
'a sort of stew' is the wordplay.
'of stew' indicates anagramming the letters (I've seen 'stewing' mean this).
'a'+'sort'='asort'
'asort' is an anagram of 'ROAST'.
(Other definitions for roast that I've seen before include "The Sunday -----, with all the trimmings!" , "Bake" , "Oven-cooked joint" , "Give a telling off to - cook" , "Criticise severely" .)