Asian dress worn by porky composer (7)
I believe the answer is:
salieri
'composer' is the definition.
(Antonio Salieri)
'asian dress worn by porky' is the wordplay.
'asian dress' becomes 'sari' (I've seen this in another clue).
'worn by' is an insertion indicator (outside letters are worn by those on the inside).
'porky' becomes 'lie' (I've seen this before).
'sari' going around 'lie' is 'SALIERI'.
(Other definitions for salieri that I've seen before include "Rival of Mozart" , "Italian composer" , "Composer contemporary with Mozart" , "musician accused of murder" .)