Charlie, unaccompanied, eating unknown Italian food (7)
I believe the answer is:
calzone
'italian food' is the definition.
(type of pizza)
'charlie unaccompanied eating unknown' is the wordplay.
'charlie' becomes 'c' (phonetic alphabet: alpha, bravo, charlie etc.).
'unaccompanied' becomes 'alone' (synonyms).
'eating' means one lot of letters goes inside another.
'unknown' becomes 'z' (algebra).
'alone' enclosing 'z' is 'alzone'.
'c'+'alzone'='CALZONE'
(Other definitions for calzone that I've seen before include "food in Venice?" , "Folded type of pizza" , "Pizza dough turnover" , "Folded variety of pizza" , "Type of pizza - clean Oz (anag)" .)