Made better, as cheddar (4)
I believe the answer is:
aged
'made better as cheddar' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for aged that I've seen before include "Got older" , "Advanced in years" , "not like a callow youth" , "Senescent" , "Very old, person or wine" .)