Cooked lamb? None for this peer of the realm (8)
I believe the answer is:
nobleman
'this peer of the realm' is the definition.
(noblemen are peers of the realm)
'cooked lamb? none' is the wordplay.
'cooked' is an anagram indicator (letters cooked into a new form).
'lamb'+'none'='lambnone'
'lambnone' anagrammed gives 'NOBLEMAN'.
'for' acts as a link.
(Other definitions for nobleman that I've seen before include "Male aristocrat" , "High-ranking male" , "I have a title" , "Peer (of realm)" , "Titled person" .)