Rarebit cooked up for the referee (7)
I believe the answer is:
arbiter
'the referee' is the definition.
(I've seen this before)
'rarebit cooked up' is the wordplay.
'cooked up' indicates anagramming the letters.
'rarebit' anagrammed gives 'ARBITER'.
'for' is the link.
(Other definitions for arbiter that I've seen before include "One who settles disputes" , "Judge - mediator" , "One must exercise judgment" , "Ref" , "Referee or judge of rarebit" .)