Layered sponge cake (8)
I believe the answer is:
sandwich
'layered sponge cake' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sandwich that I've seen before include "Snack with bread" , "See 16" , "The snack might result in bad chin wads" , "it's easy to scoff" , "The snack gives you bad chin wads" .)