Best stuff written about English (5)
I believe the answer is:
cream
'best' is the definition.
(both can mean the elite)
'stuff written about english' is the wordplay.
'stuff' becomes 'cram' (synonyms).
'written about' is an insertion indicator.
'english' becomes 'E' (abbreviation as in OED).
'cram' placed around 'e' is 'CREAM'.
(Other definitions for cream that I've seen before include "Elite; colour" , "Top of milk or society" , "An off-white shade" , "Elite; off-white" , "Elite; pale yellow" .)