Something additional found in Essex traditionally (5)
I believe the answer is:
extra
'something additional' is the definition.
(I've seen this in another clue)
'in essex traditionally' is the wordplay.
'in' says the answer is hidden in the clue.
'EXTRA' can be found hidden inside 'essex traditionally'.
'found' is the link.
(Other definitions for extra that I've seen before include "More than usual" , "Something additional or bit player in movie" , "Supplemental" , "Not a hit certainly" , "Minor actor in crowd scenes" .)