King Edward, for instance (6)
I believe the answer is:
potato
'king edward for instance' is the definition.
(King Edward is a type of potato)
This is the entire clue.
(Other definitions for potato that I've seen before include "Vegetable with eyes" , "The veg is too apt, oddly" , "Spud (6)" , "Starchy tuber" , "E.g. King Edward" .)