Table bird with top dressing (5)
I believe the answer is:
capon
'table bird' is the definition.
'capon' can be an answer for 'bird' (capon is a kind of bird). I am not sure about the 'table' bit.
'with top dressing' is the wordplay.
'with' is a charade indicator (letters next to each other).
'top' becomes 'cap' (both can mean to beat or outdo).
'dressing' becomes 'on' (I can't explain this - if you can you should believe this answer much more).
'cap' next to 'on' is 'CAPON'.
Can you help me to learn more?
(Other definitions for capon that I've seen before include "Castrated male chicken" , "Castrated rooster fattened for eating" , "Castrated cock fattened for eating" , "A tasty bird" , "one fattened specially" .)