... for each dish eaten by expert (6)
I believe the answer is:
apiece
'for each' is the definition.
('apiece' can be a synonym of 'each')
'dish eaten by expert' is the wordplay.
'dish' becomes 'pie' (I've seen this before).
'eaten by' indicates putting letters inside.
'expert' becomes 'ace' (ace is a kind of expert).
'pie' inserted inside 'ace' is 'APIECE'.
(Other definitions for apiece that I've seen before include "for everyone" , "Per person" , "A head" , "For or by each one of group" .)