A pastry with excellent topping, about a hundred each! (6)
I believe the answer is:
apiece
'each' is the definition.
(synonyms)
'a pastry with excellent topping about a hundred' is the wordplay.
I cannot quite understand how this works, but
'a' is present in the answer.
'pastry' could be 'pie' (pie is a kind of pastry) and 'pie' is found in the answer.
'about' could be 'c' (circa) and 'c' is found in the answer.
A single letter 'e' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for apiece that I've seen before include "A head" , "for everyone" , "Per person" , "For or by each one of group" .)