Swollen as a pastry (5)
I believe the answer is:
puffy
'swollen' is the definition.
(synonyms)
'a pastry' is the wordplay.
I cannot quite understand how this works, but
'pastry' could be 'puff' (puff is a kind of pastry) and 'puff' is found within the answer.
A single letter 'y' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'as' is the link.
Can you help me to learn more?
(Other definitions for puffy that I've seen before include "Swollen, soft" , "Softly inflated" .)