Choose the French gherkin (6)
I believe the answer is:
pickle
'gherkin' is the definition.
(I know that gherkin can be written as pickle)
'choose the french' is the wordplay.
'choose' becomes 'pick' (picking is a kind of choosing).
'the french' becomes 'le' ('the' in French).
'pick'+'le'='PICKLE'
(Other definitions for pickle that I've seen before include "tricky spot" , "Solution for preserving food" , "Relish; tricky situation" , "A preserved vegetable or a fine mess" , "Jam - vegetables preserved in vinegar or brine" .)