Arbiter cracked Welsh dish (7)
I believe the answer is:
rarebit
'welsh dish' is the definition.
(I've seen this before)
'arbiter cracked' is the wordplay.
'cracked' indicates an anagram.
'arbiter' with letters rearranged gives 'RAREBIT'.
(Other definitions for rarebit that I've seen before include "Arbiter (anag) -- snack" , "cheesy meal" , "mouthful?" , "Arbiter of traditional Welsh dish" , "Cheese on toast - arbiter (anag)" .)