Staple food done over heart of Italy (5)
I believe the answer is:
pasta
'staple food' is the definition.
(I know that pasta is a type of staple food)
'done over heart of italy' is the wordplay.
'done' becomes 'past' (both can mean finished).
'over' says to put letters next to each other (in a down clue, some letters go over others).
'heart of' indicates the central letters.
The middle of 'italy' is 'a'.
'past'+'a'='PASTA'
(Other definitions for pasta that I've seen before include "Plain food" , "Tagliatelle, for example" , "Spaghetti, perhaps" , "dish of food" , "Fusilli, tortelloni etc" .)