But such pastry may well be sweet (4)
I believe the answer is:
tart
This could be a double definition.
'but such pastry' is the first definition.
'tart' can be an answer for 'pastry' (type of pastry). I'm not certain of the 'but such' bit.
'well be sweet' is the second definition.
'tart' can be an answer for 'sweet' (I've seen this before). I am unsure of the 'well be' bit.
'may' is the link.
Can you help me to learn more?
(Other definitions for tart that I've seen before include "Sharp or acid tasting" , "Sharp or sour in taste" , "easy girl" , "Open-topped pie" , "See 10" .)