Agnes is ill after the French pasta dish (7)
I believe the answer is:
lasagne
'pasta dish' is the definition.
(I know that lasagne is a type of pasta dish)
'agnes is ill after the french' is the wordplay.
'is ill' indicates an anagram.
'after' means one lot of letters go next to another.
'the french' becomes 'la' ('the' in French).
'agnes' anagrammed gives 'sagne'.
'sagne' put after 'la' is 'LASAGNE'.
(Other definitions for lasagne that I've seen before include "Course" , "Fool ran as angel (anag) - pasta dish" , "Tasty Italian dish with layers of mince in pasta" , "Wide flat strips of pasta" , "Pasta served in strips" .)