Grower's Guide - March - written by Chef Consultant, Celia Brooks
Leek Love
Leeks may be considered humble, but they are truly one of the most exquisite, healthy and versatile vegetables to cook and eat. Ask any Welsh person and they will likely praise these mighty alliums – what other country has a vegetable as a national emblem? The Welsh really know their onions when it comes to leeks.
Leek are an indispensable ingredient for the foundation flavour in so many European dishes, especially soups like French vichyssoise and Scottish cock-a-leekie, and good old leek and potato soup (my own version is below). Wherever you use onions, you can use their sweeter, sexier sister, leeks.
But don’t just exploit them as a base taste element. Cooked as a solo vegetable, their unique tender layers have a luxurious texture and a super fresh and delicate flavour, especially when cooked gently with lots of moisture – they don’t take well to harsh, dry cooking. Braising is perfect, see below.
But wait – there is a very important preparation process before you cook leeks, and you mustn’t be lazy about it. Leeks grow from quite deep underground up, so soil harbours between the layers. Any leaves that are light green and separating from the stalk will have a dirty secret. Don’t throw them away though! They are the most delicious part, in my opinion. Just cut the leek lengthways from the bottom or middle of the white part, fan out the light green parts, and run them under a cold tap layer by layer until you are certain they are squeaky clean.
When you buy leeks in the supermarket wrapped in crisp plastic, most of their crowning glory has usually been cut off. Their gorgeous fan of flat dark green leaves is called the flag; this is the part of the plant that grows overground, as opposed to the shank, or the white stalk, which grows underground and is the bulk of the edible part.
The flag leaves are mostly too tough to eat (cut them off at the point where they start to pale), but I do encourage you to buy leeks from a produce vendor that is selling the flag in tact, because they make the most amazing soup stock you can imagine (see the soup recipe below). Also you’ll know they are super fresh if the flag is attached. True, you might pay more for the weight of them, but if you try boiling the (well-washed) flag with salt, you’ll surely agree that it’s worth it for the dazzling broth.
A leek with its whole flag can be up to three feet long. If you want to store these splendid giants at home for a spell without cramming them in your fridge, leave the muddy roots on and place them in a glass vase or jug full of water, like a bouquet of flowers. Change the water daily and they should keep for several days in a cool kitchen, so you can admire them for a while before you devour them.
Braised leeks: Trim the root and use the whole stem or slice thickly, steam or boil for a couple of minutes, then add to a pan with butter and and a little flavoured liquid such as white wine or Madeira, or good stock and chopped herbs like thyme, parsley and dill, and simmer until meltingly soft.
Leek in saffron orange sauce: Trim about a 500g leeks, wash and slice about 0.5cm thick. Sauté in a generous amount of butter until soft and just beginning to colour. Sprinkle in 1 Tbsp plain flour (as if making a roux) and cook for a couple of minutes, stirring. Gradually add 200ml freshly squeezed orange juice with a large pinch of saffron filaments. Season well with salt and pepper, then simmer until thick.
The Ultimate Leek & Potato Soup
From “SuperVeg” by Celia Brooks
Also known as “leek homage potage”, this leek and potato soup also features caramelised onions, but the leeks are the stars of the show. Every part of the leek is used. Leek greens make the most delicious pure soup stock – they just need to be separated layer by layer and washed before simmering in water. Each leek has a “sweet spot”, its most flavourful part, where the white turns light green, and that part is used in a special way here, sliced and poached for the perfect bright, fresh finishing garnish.
Serves 4-6
Ingredients
3 large leeks (choose leeks with as much dark green leafage still attached as possible, for making stock)
cooking salt
25g butter
1 tablespoon extra virgin olive oil
3 medium onions (about 300g), chopped
3 medium potatoes (about 500g), scrubbed but not peeled, cut into medium chunks (floury varieties work best for giving the soup body)
freshly ground black pepper
¼ teaspoon chilli flakes
Optional garnish:
crème fraiche or yoghurt, or a handful of grated cheddar cheese
Method
1) Prepare the leeks. Cut the root end off, then cut about a 5 cm / 2 inch segment where the leek turns from white to light green (the “sweet spot”, which will be reserved for poaching). Reserve all the darker green parts. Set the main white segments aside.
2) Make the pure leek stock. Separate the dark green leaves, cutting them lengthways where necessary, and rinse each layer separately and thoroughly to remove any grit. Place them in a large pan with 1.5 litres water and 1 teaspoon salt. Stir, cover and bring to the boil, then simmer while you prepare the rest of the soup.
3) Melt the butter in a soup pan over a low to medium heat and add the oil. Add the onions and cook for about 10 - 15 minutes, stirring occasionally, until very soft. Raise the heat and cook for a further 3 - 5 minutes, stirring frequently, until deep golden and caramelised.
4) Take the main white segments of the leeks and quarter them lengthways, then chop into 1 cm / ½ inch pieces. Keeping the heat medium-high, add the chopped leeks and cook for a further 5 minutes, until the leeks are collapsed and starting to colour. Add the potatoes and 1 teaspoon salt, stir well and cover. Cook for 8 - 10 minutes, stirring frequently and scraping the bottom of the pan to get all the good sticky bits incorporated – this is the stage that really develops the soup’s flavour.
5) The mixture should be turning very sticky and dark brown. Lower the heat and ladle in enough stock to fully submerge the veg, stirring between additions. (Take the stock pan off the heat.) Twist some black pepper into the soup and add the chilli flakes. Simmer for a further 10 minutes, or until the potatoes are thoroughly cooked.
6) Meanwhile, slice the reserved “sweet spots” of the leeks into 0.5cm / ¼ inch rounds (inspect them to be sure there is no dirt trapped between layers). Place in a small pan with a ladle or two of stock. Cover, bring to the boil, simmer for 5 minutes, and set aside.
7) When the soup is done, remove the pan from the heat and mash with a potato masher to break up the potatoes and thicken the broth.
8) To serve, ladle the soup into warm bowls. Use tongs to place the poached leeks on the surface of the soup and finish with a dollop of crème fraiche, yoghurt or grated cheese if desired, and a twist of black pepper.
