Burnt a piece of Camembert or Cheddar (7)
I believe the answer is:
torched
'burnt' is the definition.
(torching is a kind of burning)
'a piece of camembert or cheddar' is the wordplay.
'a piece of' indicates the answer is hidden within the clue.
'TORCHED' is hidden within 'camembert or cheddar'.
(Other definitions for torched that I've seen before include "Set fire to" , "Set alight deliberately (slang)" , "burnt" .)