Egg on sandwiches Mussolini, perhaps, made (8)
I believe the answer is:
produced
'made' is the definition.
(producing is a kind of making)
'egg on sandwiches mussolini' is the wordplay.
'egg on' becomes 'prod' (synonyms).
'sandwiches' is an insertion indicator (inserted letters are sandwiched in).
'mussolini' becomes 'duce' (I've seen this before).
'prod' enclosing 'duce' is 'PRODUCED'.
'perhaps' acts as a link.
(Other definitions for produced that I've seen before include "Made or gave rise to" , "Brought about, yielded" , "Made or presented something" , "Bore" .)