Food in Cockney character, largely (8)
I believe the answer is:
omelette
'food' is the definition.
(omelette is a kind of food)
'in cockney character largely' is the wordplay.
'in cockney' becomes ''ome' ('home' - 'he's in' can mean 'he's home' - said with the 'H' dropped - a cockney accent.).
'character' becomes 'letter' (synonyms).
'largely' means to remove the last letter (most but not all of the letters).
'letter' with its last letter taken away is 'lette'.
'ome'+'lette'='OMELETTE'
(Other definitions for omelette that I've seen before include "Item of food i" , "Cooked egg dish" , "Dish made of eggs and filling" , "breakfast" , "Broken-egg dish" .)