Something on the menu is finished article (5)
I believe the answer is:
pasta
'something on the menu' is the definition.
(type of food)
'finished article' is the wordplay.
'finished' becomes 'past' (I've seen this in another clue).
'article' becomes 'a' (the indefinite article in English).
'past'+'a'='PASTA'
'is' is the link.
(Other definitions for pasta that I've seen before include "Italian dough" , "Spaghetti, orzo etc" , "Dish of dough made with durum wheat" , "The stuff of spaghetti, macaroni etc" , "Flour and water foodstuff" .)