Cupcake topper (5)
I believe the answer is:
icing
'cupcake topper' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for icing that I've seen before include "Sweet thing" , "Maybe Madeira's topping" , "Sugar-coating" , "Sugar coating as cake decoration" , "Frosty coating" .)