The white [(onion)https://anadey.com.au/search?query=onion] base and light green stalk of the [(leek)https://anadey.com.au/search?query=leek] are edible parts. The layers that resemble onions form around a core. While the leek's tender core can be consumed, as it ages, the core turns woody and generally useless. A key component of both vichyssoise and cock-a-leekie is leeks. They work particularly well as the main ingredient in salads where they can also be used raw.