Silly fellow to singe pork pie (7)
I believe the answer is:
charlie
'silly fellow' is the definition.
(charlie can mean a foolish person)
'singe pork pie' is the wordplay.
'singe' becomes 'char' (I've seen this before).
'pork pie' becomes 'lie' ('pork pie' is Cockney rhyming slang for a lie).
'char'+'lie'='CHARLIE'
'to' acts as a link.
(Other definitions for charlie that I've seen before include "dope > (cocaine)" , "Fool - drug (slang)" , "A Bonnie Scottish Prince, or the familiar Mr McCreevy" , "-- Chaplin" , "Idiot - cocaine" .)