A top-class part pouches European gold disk (7)
I believe the answer is:
aureole
'gold disk' is the definition.
'a top-class part pouches european' is the wordplay.
'top-class' becomes 'u' (as in U and non-U speech).
'part' becomes 'role' ('role' can be a synonym of 'part'**).
'pouches' is an insertion indicator (pouch can mean to contain).
'european' becomes 'e' (abbreviation e.g. EU).
'role' going around 'e' is 'reole'.
'a'+'u'+'reole'='AUREOLE'
(Other definitions for aureole that I've seen before include "Corona round sun/moon" , "Euro ale? (anag)" , "Celestial crown or halo" .)