Man with helmet ordered cheese (9)
I believe the answer is:
emmenthal
'cheese' is the definition.
(Emmenthal is an example)
'man with helmet ordered' is the wordplay.
'with' says to put letters next to each other.
'ordered' indicates an anagram.
'man'+'helmet'='manhelmet'
'manhelmet' anagrammed gives 'EMMENTHAL'.
(Other definitions for emmenthal that I've seen before include "Something cheesy" , "Swiss cheese with holes" , "Hard Swiss cheese" , "Swiss valley giving its name to a cheese" , "Type of cheese" .)