Frosted, as a cake (4)
I believe the answer is:
iced
'frosted as a cake' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for iced that I've seen before include "Took out" , "Finished off cake" , "Decorated with sugary mixture" , "Decorated with frosting" , "Decorated (a cake)" .)