Boost canteen menu briefly with hot stew (11)
I believe the answer is:
enhancement
'boost' is the definition.
(thesaurus)
'canteen menu briefly with hot stew' is the wordplay.
'briefly' means to remove the last letter.
'with' says to put letters next to each other.
'hot' becomes 'h'.
'stew' indicates anagramming the letters.
'canteen'+'menu'='canteenmenu'
'canteenmenu' with its last letter taken off is 'canteenmen'.
'canteenmen'+'h'='canteenmenh'
'canteenmenh' anagrammed gives 'ENHANCEMENT'.
(Other definitions for enhancement that I've seen before include "Boost, intensification" , "this will improve things" , "Improving change" , "Heightening" , "What improves" .)