Covered in frosting (4)
I believe the answer is:
iced
'covered in frosting' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for iced that I've seen before include "hidden under white crystals?" , "Dressed in a sweet coat" , "Covered with flavoured sugar topping" , "Core; card; organ" , "Decorated with frosting" .)