Unsurpassed as chicken served in veloute sauce? (7)
I believe the answer is:
supreme
I believe this is a double definition.
'unsurpassed' is the first definition.
(both can mean unbeaten or unbeatable)
'as chicken served in veloute sauce?' is the second definition.
(as in the dish chicken supreme)
(Other definitions for supreme that I've seen before include "Greatest in status, authority or power" , "creamy dish of chicken perhaps" , "Crowning" , "Creamy sauce" , "Cardinal, foremost" .)