Work serving out soup (4)
I believe the answer is:
opus
'work' is the definition.
(an opus is an artistic work)
'out soup' is the wordplay.
'out' is an anagram indicator.
'soup' is an anagram of 'OPUS'.
'serving' acts as a link.
(Other definitions for opus that I've seen before include "Work (mus.)" , "Artistic work" , "Composer's work" , "Major work" , "Piece of music (with number)" .)