Potato & Leek soup is a classic French soup known as potage parmentier, or in its chilled form as vichyssoise. Made with a few simple ingredients, the soup is thick, hearty and satisfying.
Coming together quickly, this potato & leek soup is perfect for a quick meal - serve with some crusty bread or a sandwich if you're particularly hungry - or as a starter for a French themed dinner party.
Ingredients for Potato & Leek soup
- Leeks
- Onion
- Butter
- Potato - use a floury potato or an all rounder. Avoid waxy potatoes because they won't break down and thicken the soup.
- Vegetable stock - ideally use home made or a quality store bought stock that's low in salt. In a pinch you can use water or a stock cube/powder.
- Cream
To serve:
- A basic option to garnish the soup is to use a drizzle of extra virgin olive oil and some finely sliced chives.
- If you want to go all out, try:
- Italian salsa verde - but without the anchovies. If you make my recipe, make a 1/4 size batch for 4 soup serves.
- Croutons
- Finely sliced chives.
Essential equipment to make Potato & Leek soup
You'll need one of the following for this soup in order to purée the soup:
- Blender
- Stick blender
- Food processor
Step-by-step guide to making Potato & Leek soup
Prep - start by preparing the leeks and onion. Cut the tops of the leeks off, where they turn green. Halve the leek lengthways and then slice them. Peel and then slice the onion. Peel the potato and coarsely chop them.
Wash leeks - add the sliced leeks to a large bowl and cover with water. Agitate the leeks with your hand to remove all the dirt. Allow to stand for a minute or so, and then get a strainer and pick the leeks up from the bowl they're soaking in and drain them and give them one last rinse. Be careful not to pick the dirt up from the bottom of the bowl.
Sauté - heat a large pot or Dutch oven over medium heat. Add the butter, leeks and onions (1) and stir regularly. Cook for about 8 minutes until the onion is translucent and the leek is soft (2).
Add the potatoes and stock to the pot and increase heat to high. Bring to the boil and then reduce heat to a simmer. Cover and cook for 15-20 minutes until the potatoes are tender and just starting to fall apart.
Blend - remove the soup from the heat and allow to cool slightly for 5 minutes or so. Blend the soup using a blender, stick blender or food processor (1). Take care not to over blend, because the potato can make the soup gloopy. Stir through the cream (2).
Serving - It's traditional to serve with chives, and a drizzle of olive oil will help accentuate the chive flavours. If you want to make the soup a little fancier, I suggest making Italian salsa verde - leave out the anchovies - and drizzle that over the soup, top with croutons and some chives. See the post for other serving ideas.
Tips
- Thoroughly clean your leeks - after slicing, soak them in a bowl of cold water, agitate gently, then lift them out, leaving the grit behind. You don't want your soup gritty from not washing the leeks properly!
- Cook the leeks and onion slowly - aim for soft & translucent, not browned.
- Cool before blending - this reduces the risk of burns from hot soup and will prevent the cream from splitting when added.
- Adjust the soup consistency - after blending, if the soup is too thick, thin it with a bit of extra stock or water. If it's too thin, simmer gently to reduce.
- If you are making ahead or have leftovers, garnish before serving. Putting the garnishes on before placing in the fridge won't work.
- Don't over blend the soup, because it can make it gloopy from the potato starch.
Vichyssoise
Vichyssoise is essentially Potato and Leek soup (which is known in French as potage parmentier) that is served chilled, ideally as a summer soup, in the same way you'd serve gazpacho soup.
This recipe is suitable to make Vichyssoise from; just increase the cream to 1 cup for the standard serve - up from 1/2 cup.
Serve the vichyssoise as room temperature or chilled.
Toppings or garnishes for Potato & Leek soup
Traditionally, Potato & Leek soup is served with finely sliced chives. I like to add a little drizzle of extra virgin olive oil which adds a little more richness and carries the flavour of the chives.
If you're cooking to impress, I like to serve this with
- Italian salsa verde - but without the anchovies. If you make my recipe, make a 1/4 size batch for 4 soup serves.
- Croutons - simply cut two slices of rustic bread, preferably sourdough into approx 2cm (3/4") wide slices. Cut into 2cm (3/4") cubes, add a good drizzle of extra virgin olive oil - about 2 tbsp - and stir well to combine. Bake for 10-15 minutes at 180C, turning every 5 minutes until golden.
- Finely sliced chives for a little more herby pop.
You could also try:
- A dollop of sour cream or crème fraîche.
- Crispy bacon or pancetta lardons.
Make ahead, reheating and freezing Potato & Leek soup
The soup is easily made ahead of time and will keep in the fridge for around 4 days. Don't add any garnishes until you're serving - they will go soggy while they're in the fridge if you put them in the soup.
Reheat in the microwave or in a small pot over medium heat.
You can freeze the soup, but the texture can suffer because potatoes tend to get mealy when frozen. Keep frozen for up to 3 months and defrost overnight in the fridge or in the microwave before use. If the texture has suffered while freezing, blending it again can help.
Add your own touch
None of these options are traditional, but here are some ideas you can use to put your own twist on Potato & Leek soup:
- Experiment with garnishes and toppings.
- Try a herbed oil (minced basil and parsley with extra virgin olive oil)
- Grated cheese, or cheesy croutons.
- Toast some almonds or pine nuts.
- Fry up some leeks and/or garlic and top the soup with that.
- Change the salsa verde up for gremolata.
- Try adding some spices like smoked paprika while sautéing the onion & leeks.
Authenticity note
I've recommended the soup with an Italian salsa verde if you want to be a little fancy. This is not authentically French, nor is the drizzle of olive oil.
Potato & Leek soup
| Prep | Cook | Total |
|---|---|---|
| 10 mins | 25 mins | 35 mins |
- 400g leeks, washed, halved lengthways and sliced this is around 2 average leeks - see note 1
- 1 medium onion, sliced
- 50g butter
- 400g potatoes, large diced around 2-3cm - use a floury potato, see note 2
- 1L vegetable stock see note 3
- 125ml (1/2 cup) cream or 1 cup if you'd like a richer soup or if you're making vichyssoise
- Salt & pepper, to taste preferably white pepper, see note 4
- Drizzle of extra virgin olive oil
- Chives, finely sliced see note 5 for other suggestions
- Salsa verde make 1/4 of recipe and leave out the anchovies, see note 5
- Croutons see note 6
- Chives, finely sliced
- Prep - start by preparing the leeks and onion. Cut the tops of the leeks off, where they turn green. Halve the leek lengthways and then slice them. Peel and then slice the onion. Peel the potato and cut them into large dice.
- Wash leeks - add the sliced leeks to a large bowl and cover with water. Agitate the leeks with your hand to remove all the dirt. Allow to stand for a minute or so, and then get a strainer and pick the leeks up from the bowl they're soaking in and drain them and give them one last rinse. Be careful not to pick the dirt up from the bottom of the bowl.
- Sauté - heat a large pot or Dutch oven over medium heat. Add the butter, leeks and onions and stir regularly. Cook for about 8 minutes until the onion is translucent and the leek is soft.
- Add the potatoes and stock to the pot and increase heat to high. Bring to the boil and then reduce heat to a simmer. Cover and cook for 15-20 minutes until the potatoes are tender and just starting to fall apart.
- Blend - remove the soup from the heat and allow to cool slightly for 5 minutes or so. Blend the soup using a blender, stick blender or food processor. Take care not to over blend, because the potato can make the soup gloopy. Stir through the cream.
- Serving - It's traditional to serve with chives, and a drizzle of olive oil will help accentuate the chive flavours. If you want to make the soup a little fancier, I suggest making Italian salsa verde - leave out the anchovies - and drizzle that over the soup, top with croutons and some chives. See the post for other serving ideas.
- Leeks - leeks grow beneath the ground and as such often have a large amount of sand and dirt in them. Make sure you wash them well. I like to soak in a large container and rub through my hands, and then scoop them out with a strainer.
- Potatoes - use a floury potato, not a waxy one. You want the potato to fall apart in the soup as it cooks to thicken it.
- Vegetable stock - for the absolute best results, use a homemade vegetable stock or quality packaged stock. If you're using store-bought, use a salt reduced stock so you can season to your taste.
- Salt & pepper - preferably use white pepper to avoid black specks in the soup.
- Serving suggestions - traditionally this soup is served with just a drizzle of olive oil and some chives. If you want to get a bit fancier, serve it with croutons, salsa verde and finely sliced chives. A store bought salsa verde is fine, but if you make my recipe I suggest leaving out the anchovies in this instance. You could also try a dollop of sour cream or crème fraîche, or bacon or pancetta lardons that have been fried crispy.
- Croutons - to make croutons, use two slices of rustic bread cut approx 2cm (3/4") wide. Cut into 2cm (3/4") cubes, add a good drizzle of extra virgin olive oil - about 2 tbsp - and stir well to combine. Bake for 10-15 minutes at 180C, turning every 5 minutes until golden.
- Vichyssoise - essentially potato & leek soup that's eaten cold. This recipe is suitable for both vichyssoise (cold) and the warm potato & leek soup potage parmentier. Increase cream to 1 cup if making vichyssoise or if you'd like the warm soup to be creamier.
- Blending - be careful not to blend too long, as it can make the soup gloopy. The potato will naturally break down as the soup cooks.
- Garlic - I'm generally not a fan of garlic in soups and potato & leek soup traditionally does not have garlic in it. If you'd like to add garlic, you can add 2 minced garlic cloves about a minute before you add the potatoes and stock.
- Gloopy soup - avoid over processing the soup as doing so can activate the potato starch which will thicken the soup too much.
