Rat's head Olivia cooked for food parcels (7)
I believe the answer is:
ravioli
'food parcels' is the definition.
(I've seen this before)
'rat's head olivia cooked' is the wordplay.
'head' suggests taking the first letters.
'cooked' indicates anagramming the letters.
The first letter of 'rats' is 'r'.
'olivia' anagrammed gives 'avioli'.
'r'+'avioli'='RAVIOLI'
'for' acts as a link.
(Other definitions for ravioli that I've seen before include "Italian pillow-shaped pasta" , "Pasta envelopes with savoury filling" , "Pasta with savoury stuffing" , "2 [PASTA]" , "Pasta resembling pillowcases" .)