Ultimately implausible claims about the French food (7)
I believe the answer is:
edibles
'food' is the definition.
(I know that food can be written as edibles)
'ultimately implausible claims about the french' is the wordplay.
'ultimately' indicates one should take the final letters.
'claims' becomes 'dibs' (I've seen this in another clue).
'about' indicates putting letters inside.
'the french' becomes 'le' ('the' in French).
The final letter of 'implausible' is 'e'.
'dibs' placed around 'le' is 'dibles'.
'e'+'dibles'='EDIBLES'
(Other definitions for edibles that I've seen before include "Food" , "Things fit to eat" , "Things fit to be eaten" .)