What serves diners a feta-rice mix? (9)
I believe the answer is:
cafeteria
'what serves diners' is the definition.
'a feta-rice mix?' is the wordplay.
'mix?' is an anagram indicator (I've seen 'mixes' mean this).
'a'+'feta'+'rice'='afetarice'
'afetarice' anagrammed gives 'CAFETERIA'.
(Other definitions for cafeteria that I've seen before include "Where one scoffs" , "dining-room" , "Place to eat" , "Canteen" , "Self-service restaurant" .)