Each expert consumes pastry dish (6)
I believe the answer is:
apiece
'each' is the definition.
('apiece' can be a synonym of 'each')
'expert consumes pastry dish' is the wordplay.
'expert' becomes 'ace' (ace is a kind of expert).
'consumes' is an insertion indicator.
'pastry dish' becomes 'pie' (I've seen this before).
'ace' going around 'pie' is 'APIECE'.
(Other definitions for apiece that I've seen before include "For or by each one of group" , "A head" , "Per person" , "for everyone" .)