Portion of quail leg -- a luxury that could be banned (7)
I believe the answer is:
illegal
'be banned' is the definition.
(similar in meaning)
'portion of quail leg a luxury that' is the wordplay.
'portion of' indicates the answer is hidden within the clue.
'ILLEGAL' can be found hidden inside 'quail leg a luxury that'.
'could' acts as a link.
(Other definitions for illegal that I've seen before include "Felonious" , "Contraband" , "Against the rules" , "Ignoring certain acts" , "Black" .)