Genesis setting (4)
I believe the answer is:
'genesis setting' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eden that I've seen before include "Perfect place" , "Tory Prime Minister, 1955-57" , "PM, 1955-57" , "5,27 [PRIME MINISTER]" , "Former British PM - unspoilt paradise" .)