For each pastry one consumes (6)
I believe the answer is:
apiece
'for each' is the definition.
(synonyms)
'pastry one consumes' is the wordplay.
'pastry' becomes 'pie' (pie is a kind of pastry).
'one' becomes 'ace' (ace has a value of one in some card games).
'consumes' indicates putting letters inside.
'pie' going into 'ace' is 'APIECE'.
(Other definitions for apiece that I've seen before include "Per person" , "A head" , "for everyone" , "For or by each one of group" .)