Pastries in Impressionist art school (5)
I believe the answer is:
tarts
'pastries' is the definition.
(I know that tart is a type of pastries)
'in impressionist art school' is the wordplay.
'in' indicates the answer is hidden within the clue.
'TARTS' is hidden in the letters of 'impressionist art school'.
(Other definitions for tarts that I've seen before include "Broads" , "Flans" , "Small open pies" , "Open pastries" , "Hookers" .)