With expert knowledge, evidently, family produces fine paper (9)
I believe the answer is:
onionskin
'paper' is the definition.
(type of thin paper)
'with expert knowledge evidently family produces fine' is the wordplay.
I cannot really understand how this works, but
'family' could be 'kin' (synonyms) and 'kin' is located in the answer.
'produces' could be 'onions' (onion is a kind of produce) and 'onions' is located in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for onionskin that I've seen is " Very thin variety of paper".)