The spuds Buster mashed? (6)
I believe the answer is:
'the spuds' is the definition.
Although both the answer and definition are plural nouns, I don't see how one could define the other.
'buster mashed?' is the wordplay.
'mashed?' indicates anagramming the letters (I've seen 'mash' mean this (letters mashed up)).
'buster' anagrammed gives 'TUBERS'.
Can you help me to learn more?
(Other definitions for tubers that I've seen before include "Kind of potatoes - real brutes (6)" , "Wrongly rebuts the potatoes, say" , "Potatoes, for instance" , "spuds etc" , "Potatoes and dahlias, say" .)