Swiss city's cash accommodating European composer (9)
I believe the answer is:
bernstein
'composer' is the definition.
(Leonard Bernstein)
'swiss city's cash accommodating european' is the wordplay.
'swiss city's' becomes 'Bern's' (Bern is the capital of Switzerland).
'cash' becomes 'tin'.
'accommodating' means one lot of letters goes inside another.
'european' becomes 'E' (abbreviation e.g. EU).
'tin' placed around 'e' is 'tein'.
'berns'+'tein'='BERNSTEIN'
(Other definitions for bernstein that I've seen before include "Noteworthy personality" , "Mass producer" , "scoring ace" , "composer" , "Leonard --, American conductor" .)