Three-Cornered Leek And Potato Soup
A fresh spring riff on classic leek and potato soup, this three-cornered leek soup recipe is a brilliant way to use foraged three-cornered leeks, which seem to pop up everywhere at this time of year. Creamy, mild and full of delicate onion flavour, it’s a thrifty, seasonal bowl that’s wonderfully easy to make.
Spring is my absolute favourite season. I love the colours, the freshness and the emerging spring greens just ripe for foraging and making delicious recipes with. Three-cornered leeks are the first to shoot up and they’re incredibly abundant in my neck of the woods. So this soup is usually the first recipe of the year I make from foraged greens.
Dive Right In
- What Is Three-Cornered Leek?
- Why You’ll Want To Make This Soup
- Three-Cornered Leek Soup
- Ingredients, Additions And Substitutions
- How To Make Three-Cornered Leek and Potato Soup
- Other Recipes Using Wild Greens You Might Like
- Keep In Touch
- Pin It
- The Recipe
What Is Three-Cornered Leek?
This rather pretty wild allium (Allium triquetrum) is known by many names here in the UK. Because of its flavour and triangular leaf shape, it’s most commonly called three-cornered leek. Other names include: onion weed, snowbell, three-cornered garlic, onion grass and stinking onion. The less said about this last one the better.
Although it’s commonly found in most parts of the UK, it’s not actually native. It was introduced from the Mediterranean in the 18th Century. In fact it’s now so invasive it’s illegal to plant or propagate it.
As its names suggest it’s a member of the onion family and all parts of it are edible. It sort of tastes like a cross between baby leeks, chives and mild garlic. The leaves make excellent soup and the flowers are lovely as a salad garnish.
The only recipe where it’s featured so far on Tin and Thyme is in these spanakopita pastries.
For more information on the three cornered leek and for identification, Wild Food UK has a useful page on it.
Why You’ll Want To Make This Three-Cornered Leek and Potato Soup
There’s something rather special about the first proper spring soup of the year. Lighter than the stews of winter, yet still comforting enough for cooler evenings, this three-cornered leek and potato soup captures the season in a bowl.
- Celebrate the arrival of spring – Three-cornered leeks appear just as winter comfort food starts to feel heavy. Their fresh, mild onion flavour captures that shift in seasons beautifully – light, green and full of promise.
- A brilliant way to use foraged food – Allium triquetrum grows abundantly in many parts of the UK and Ireland, often in shady lanes, hedgerows and woodland edges. Turning something freely gathered into a nourishing meal is deeply satisfying.
- Wonderfully thrifty – Foraged greens mean fewer shop-bought ingredients. Pairing them with humble potatoes keeps costs low while still producing a filling, flavourful meal. It’s proof that simple ingredients can create something special.
- Reduces food miles – Wild greens gathered locally travel just a few steps from patch to pot. That’s about as low-impact and seasonal as food can be.
- Comforting but not heavy – Potato gives the soup body and a little cream makes it deliciously smooth. But the star of the show makes it light enough for brighter days.
- Makes the most of an abundant plant – In some areas, three-cornered leek is considered invasive. Harvesting it responsibly can actually help manage its spread – a win for cooks and ecosystems alike.
- Delicate fresh flavour – Milder than wild garlic, three-cornered leek has a delicate sweetness that pairs beautifully with potatoes. The result is fragrant rather than overpowering.
- Nutrient-rich and wholesome – Like other alliums, three-cornered leeks contain beneficial plant compounds and when combined with potatoes, you have fibre, vitamin C and slow-release energy in one bowl.
Three-Cornered Leek Soup
Made with freshly foraged three-cornered leeks and humble potatoes, this soup recipe is thrifty, fragrant and beautifully simple. Even better, if you have a patch growing nearby, it transforms an abundant wild green into a nourishing meal with hardly any expense at all.
The only thing you really need to splash out on is a pot of cream. It’s a true taste of spring, gathered and simmered gently on the stove.
When three-cornered leeks are not in season or you just can’t find any, use leeks instead. This gives you a classic leek and potato soup.
The recipe makes four decent sized portions. However, it could easily run to six people as a light lunch or even eight people if served as a starter.
I like to serve the soup with these easy yoghurt breadsticks or cheese scones in order to get a well balanced protein meal. But the soup is actually delicious just by itself.
A sprinkling of toasted pumpkin seeds are a firm favourite. They are extremely nutritious and provide a good contrasting crunch. I roast mine in the air fryer with a drizzle of olive oil and a little tamari. Yum!
Ingredients, Additions and Substitutions
Other than the three-cornered leeks, you need very little to make this soup recipe. There are a few ingredients worth mentioning though.
Cheese Rind
I always save the hard rinds of cheese rather than disposing of them. Italian hard cheeses like vegetarian parmesan are particularly useful. They’re just brilliant for soups. They add umami notes to simple veg soups like this one as well as a bit of protein.
Adding an edible cheese rind is entirely optional. However, if you’d like to add some cheesy umami notes, you can use a couple of tablespoons of nutritional yeast instead.
Cream
Double cream adds richness to the soup as well as smoothness. I don’t use a lot, but it makes a big difference. If you’d like to keep the soup plant-based, use some coconut cream instead. This will change the flavour profile though.
Potato
You can use any potatoes for this recipe, but floury ones such as Maris Piper and King Edward are best. They’ll give a creamier and smoother consistency to the soup.
Vegetable Stock
A light vegetable stock works best in this soup. You want to enhance its flavour and not overwhelm the delicate notes of the three-cornered leeks.
I often use water leftover from boiling vegetables, such as carrots, peas or cauliflower. Otherwise I use vegetable bouillon powder, but don’t add very much.
How To Make Three-Cornered Leek And Potato Soup
If you have a soup maker, this recipe is incredibly easy. If you don’t it’s almost as easy to make it on the stove top. You will need some kind of blender though.
Please refer to the recipe card at the bottom of this post for cooking temperatures and quantities of ingredients used.
Prepare Veg
Scrub the potato, but don’t worry about peeling it unless it’s in a particularly bad state. Chop it into rough chunks then add to your soup maker or large saucepan.
Wash the three-cornered leeks really well in at least two changes of water. I usually go three. The triangular nature of the leaves tend to trap bits of soil. Drain briefly in a colander or give them a good shake, then chop them into roughly 6cm (2 inch) lengths.
This not only helps them to cook, but makes blending easier later.
Reserve a few for snipping over the soup later.
Soup Maker Method
Place everything except the double cream and reserved leaves into a soup maker and let it do its thing. My power blender also works as a soup maker and takes exactly thirty minutes.
Once finished, test for seasoning and add a little more salt or pepper if you think it needs it.
Pour in the cream, then blend briefly to combine.
Stove Method
Place everything except the double cream and reserved leaves into a large saucepan. Put the lid on and bring to the boil. Turn the heat down and simmer for fifteen minutes or until the potatoes are completely soft.
Take off the heat and blend until smooth using a stick blender. A jug blender will give a smoother result, but requires more in the way of washing up.
Taste test and add more seasoning if you think it needs it.
Add the cream and blend briefly again.
To Serve
Divide the soup between bowls, then snip the reserved leaves over the tops to decorate. A swirl of cream always looks nice and roasted pumpkin seeds add crunch as well as a bit of protein.
Any leftover soup will keep in a covered container in the fridge for a couple of days. Just reheat when needed.
You can also freeze the soup in an airtight freezer-proof container for up to four months. Allow to thaw overnight in the fridge, then reheat and blend again to revive the smooth creamy consistency.
Other Recipes Made With Wild Greens You Might Like
- Fat hen & chickweed pesto
- Green flatbreads with wild garlic & nettles
- Nettle soup
- Samphire noodles with miso marinated tofu
- Wild garlic pesto: two ways
- Wild garlic tofu patties
Keep in Touch
Thank you for visiting Tin and Thyme. If you make this three-cornered leek and potato soup, I’d love to hear about it in the comments below. Do you have any recommendations or tips for picking or cooking with this rather delicious weed?
Please rate the recipe too. And do tag me @choclette8 on Instagram with your images, I really enjoy seeing your take on my recipes.
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If you’d like more soup recipes, follow the link and you’ll find I have quite a lot of them. All delicious and nutritious, of course.
Choclette x
Three-Cornered Leek and Potato Soup. PIN IT.
Three-Cornered Leek And Potato Soup
Ingredients
- 225 g potato starchy ones are best – no need to peel
- 225 g three-cornered leeks or swap for leeks – well washed and roughly chopped
- 20 g Italian hard cheese rind (optional)
- ¾ tsp sea or rock salt
- ¼ tsp freshly ground black pepper
- 1 litre vegetable stock (I used 1 litre of water with 1 ½ tsp light vegetable bouillon)
- 100 ml double cream
Instructions
Soup Maker Method
- Place everything except the double cream into a soup maker and let it do its thing.225 g potato, 225 g three-cornered leeks, 20 g Italian hard cheese rind, ¾ tsp sea or rock salt, ¼ tsp freshly ground black pepper, 1 litre vegetable stock
- Once finished, test for seasoning and add a little more salt or pepper if you think it needs it. Mine takes thirty minutes exactly.
- Pour in the cream, then pulse briefly to combine.100 ml double cream
Stove Method
- Place everything except the double cream into a large saucepan. Put the lid on and bring to the boil. Turn the heat down and simmer for 15 minutes or until the potatoes are completely soft.225 g potato, 225 g three-cornered leeks, 20 g Italian hard cheese rind, ¾ tsp sea or rock salt, ¼ tsp freshly ground black pepper, 1 litre vegetable stock
- Take off the heat and blend until smooth with a stick blender, or jug blender if you prefer.
- Taste test and add more seasoning if you think it needs it.
- Add the cream and blend once again.100 ml double cream
To Serve
- Pour into bowl then snip the reserved onion weed over the soup to decorate. A swirl of cream always looks nice and roasted pumpkin seeds add crunch as well as a bit of protein.
I read this post with interest because I tried to grow leeks once and they never grew very big and I ended up using them instead of chives or spring onions. I don’t think they were the three cornered leeks but were similar. I am fascinated that these grow wild in the UK – not sure if we have them in Australia. They must look gorgeous when there are a lot of them (as is too often the case with invasive plants so they leave me with mixed feelings).
The soup looks lovely and so wonderfully green. My favourite soup to make in spring is a spring risotto soup with lots of green vegies – and much greener and easier (no constant stirring) than a traditional risotto.
I love the sound of your air fryer tamari pepitas – I must try some roasted nuts and seeds in the air fryer!
Lovely to hear from you Johanna. I think you do have three-cornered leeks growing wild as an invasive species in Australia too. You may know them as onion weed or angled onion. Definitely worth harvesting if you ever come across any. They’re really pretty when the white flowers come out, which I’m guessing is why they were introduced. Leeks are a bit tricky to grow, they like it fairly damp. I always roast my nuts and seeds in the air fryer now – easy and quick. And your risotto soup sounds like a lovely idea – I do love a green soup in the spring.
If everyone along the south coast has this recipe and knew how to use the incredibly invasive three cornered leek- there would be a lot less use of weed killer along pavements and garden edges. Thank you Nicette!
This is very true and a much much better idea to eat the stuff than zap it with poisons. I made it again today, only this time I added nettles. Delicious.
If you lived nearby I could bring you armloads of these plants but they are the bane of my life! Come the Spring they pop up all over the garden. One thinks they have removed them and their bulbs but back they come with renewed vigour next spring. After mowing the lawn the smell is overwhelming. I think I’ll leave the soup for you although I think it would be very tasty. :))
Mary :))
Oh dear Mary, that doesn’t sound good. I feel your pain as we have lots of plants that do just that in our garden (though they don’t smell of onion). Luckily we don’t have this particular one in the garden, but they’re a pernicious weed here in the UK too and we’re not allowed to propagate them. But it does mean you can harvest them in the wild with impunity. And they do taste good.