Jam and cake, perhaps (5)
I believe the answer is:
wedge
'jam' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for wedge that I've seen before include "Tapering block" , "Piece of wood thick at one end, thin at other" , "Tapering piece" , "Type of shoe" , "Jam" .)