Having dished out in advance, kept (9)
I believe the answer is:
preserved
'kept' is the definition.
('preserve' can be a synonym of 'keep')
'having dished out in advance' is the wordplay.
I cannot really understand how this works, but
'dished' could be 'served' ('serve' can be a synonym of 'dish') and 'served' is found in the answer.
'in advance' could be 'pre' (prefix meaning 'before') and 'pre' is present 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?
(Other definitions for preserved that I've seen before include "Prevented from decay" , "Kept in an unaltered condition" , "Prevented from decaying or spoiling" , "Maintained in an unaltered condition" , "Kept safe from harm" .)