See wriggly insect served up in comfort food (12)
I believe the answer is:
cheeseburger
'food' is the definition.
(cheeseburger is a kind of food)
'see wriggly insect served up in comfort' is the wordplay.
'wriggly' is an anagram indicator (I've seen this in other clues).
'insect' becomes 'grub' (a grub is an insect larva).
'served up' says the letters should be written backwards (in a down clue, going upwards).
'in' means one lot of letters goes inside another.
'comfort' becomes 'cheer' (cheer can mean to comfort or gladden someone).
'grub' written backwards gives 'burg'.
'see' with letters rearranged gives 'ese'.
'ese'+'burg'='eseburg'
'eseburg' inserted into 'cheer' is 'CHEESEBURGER'.
(Other definitions for cheeseburger that I've seen before include "Fast food product" , "Fast food -- begs cure here (anag)" , "filled roll" , "Fast food item" , "Fast food snack" .)