Onionlike soup ingredient (4)
I believe the answer is:
leek
'onionlike soup ingredient' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for leek that I've seen before include "Vegetable associated with Wales" , "what Fluellen wore in France?" , "Plant; Welsh emblem" , "Welsh national emblem" , "Plant (onion relative) eaten as a vegetable" .)