Very sensitive child fed a variety of crepes (3,6)
I believe the answer is:
top secret
'very sensitive' is the definition.
(top secret means very sensitive or classified)
'child fed a variety of crepes' is the wordplay.
'child' becomes 'tot' (term for a young child).
'fed' is an insertion indicator (one word is 'fed' to another).
'a variety of' indicates an anagram.
'crepes' is an anagram of 'psecre'.
'tot' enclosing 'psecre' is 'TOP-SECRET'.
(Other definitions for top secret that I've seen before include "As Bond mission" , "label on some classified documents" , "Known to very few" , "Highly confidential" , "Erect post (anag)" .)