Stew ingredient (4)
I believe the answer is:
leek
'stew 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 "Onion's relative" , "Vegetable of the onion family" , "National emblem of Wales." , "English town" , "Edible plant, Welsh symbol" .)