Girl eating cheese is an angel (7)
I believe the answer is:
gabriel
'an angel' is the definition.
(the archangel Gabriel)
'girl eating cheese' is the wordplay.
'girl' becomes 'gal'.
'eating' indicates putting letters inside.
'cheese' becomes 'brie' (Brie is an example).
'gal' placed around 'brie' is 'GABRIEL'.
'is' is the link.
(Other definitions for gabriel that I've seen before include "Trumpet-playing archangel who heralded good news" , "Boy" , "Archangel who plays the trumpet" , "Angel of Annunciation" , "Man'" .)