Leek
Allium ampeloprasum · Welsh leek (national symbol of Wales)
The leek is the gentlest and most versatile of the alliums. It lacks the pungency of onion or the intensity of garlic, offering instead a sweet, mild, slightly buttery flavour that makes it ideal for soups, gratins and braised dishes where a background allium note is wanted without dominance. It is also among the most seasonally appropriate vegetables for winter cooking in Britain, being at its best from October through February.
Mild, sweet and subtly onion-like when cooked. Far gentler than onion or shallot. The flavour is clean and slightly buttery, with a faint anise note from the natural sulphur compounds (thiosulfinates) common to all alliums.
Layers of crisp, slightly waxy leaves raw. When cooked in butter until soft: silky and melting with no fibrous resistance. The outer layers are tougher than the inner; trim or cook for longer if the outer layers feel stringy.
Refrigerate loosely wrapped for up to 1 week. The white and light green parts are the most tender; the dark green tops can be used in stocks. Do not freeze raw.
Trim the roots and the dark green tops. Halve lengthways and wash thoroughly under running water — grit lodges between the layers. For soups and braises: slice into rounds or half-moons. For braising whole: leave the white and pale green part intact, braise in butter and stock. For gratins: slice thinly.