Slapstick comedy prop (7,3)
I believe the answer is:
custard pie
'slapstick comedy prop' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for custard pie that I've seen before include "It's thrown for laughs" , "But is one thrown" , "Slapstick missile" , "Element of slapstick" , "Clown's dessert?" .)