Rod served up a little waffle or bun (6)
I believe the answer is:
rabbit
'bun' is the definition.
(I know that bun can be written as rabbit)
'rod served up a little' is the wordplay.
'rod' becomes 'bar' (I've seen this before).
'served up' says the letters should be written in reverse (in a down clue, going upwards).
'a little' becomes 'bit' (both can mean a small amount of something).
'bar' reversed gives 'rab'.
'rab'+'bit'='RABBIT'
'waffle or' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
(Other definitions for rabbit that I've seen before include "Yak" , "Animal called coney" , "Fast-breeding hopper" , "Chatter; poor games-player" , "one found in the tail" .)