Cream the French relish (6)
I believe the answer is:
pickle
'relish' is the definition.
(pickle is a kind of relish)
'cream the french' is the wordplay.
'cream' becomes 'pick' ('pick' can be a synonym of 'cream').
'the french' becomes 'le'.
'pick'+'le'='PICKLE'
(Other definitions for pickle that I've seen before include "A preserve or an informal predicament" , "Relish, difficult situation" , "tricky spot" , "Immerse (object) in acid" , "Mischief-maker" .)