This leek soup, also known as potage parmentier, is a deliciously creamy potato soup made with a favorite French vegetable — leeks! This healthy leek soup comes together in just under 30 minutes, making it a wonderfully easy meal to dish up as an appetizer for a dinner party, or just lunch or dinner during the week.
Leek Soup (Potage Parmentier)
The French are obsessed when it comes to leeks, which I find amusing as most Americans hardly ever use this pungent vegetable. The French love the vegetable so much, they dedicated a whole soup to it.
Leek soup pretty much consists of two main ingredients: potatoes and leeks. This is why the soup is often referred to as potato leek soup, or sometimes just potato soup (though that seems less accurate to me).
Because leeks have such a strong, almost onion-like flavor, this otherwise creamy potato soup recipe really doesn’t need anything else to spruce it up.
How to Clean Leeks
The only reason this leek soup could never be a chop, dump, and purée soup like, say, a winter squash soup is because leeks need a thorough cleaning before they’re actually chopped up and added to the soup.
Leeks are notorious for hidden sand and grit in between their tightly packed leaves. That said, you’ll find cleaning leeks to be much easier than chopping up a butternut squash or pumpkin for a winter puréed soup.
To clean your leeks, you’ll simply want to cut the leek in half, lengthwise, so that you have two long halves. Then, you’ll want to take each half and rinse it under cool running water, pulling every leaf back to make sure you rinse any grit stuck between each leaf.
Other than taking the time and attention to carefully rinse each leek, there’s really not much else to cleaning leeks.
Potato Leek Soup No Cream
To make this a healthy leek soup, you can skip adding any cream to this recipe. When the potatoes are puréed in a food processor, they become incredibly smooth and creamy. If you’ve ever made mashed potatoes with an immersion blender, you’ll understand exactly what I’m describing.
Because of this smooth and creamy consistency, this leek soup doesn’t need heavy cream to obtain the proper texture or consistency. Instead, if you choose to add a tablespoon or two of cream at the end, it will only enhance the richness of the soup’s flavor.
Vegan Leek Soup
If you’ve seen Julia Child’s recipe for potage parmentier, it doesn’t contain any stock, although it does suggest butter for sautéeing the leeks in. Aside from the butter, however, Julia Child suggests adding water to cook the potatoes and leeks in.
While water will do in a pinch, I prefer using stock when preparing a soup (or stew) that doesn’t have any meat, poultry or starter pork fat (i.e. bacon, pancetta). You’ll notice I use chicken stock in this recipe as I find it adds some nice flavor to the soup.
To make this a vegan leek soup, however, you can swap out the butter in this recipe for olive oil and the chicken stock for vegetable stock.
Serving Potage Parmentier
Leek soup can be a really heavy dish because of the potatoes, so I suggest serving the soup as a small starter. Instead of serving two cups of soup (or two people), it seems more suitable to break the soup down into 4 small 1/2 cup servings.
In my experience, potage parmentier is best served in small bowls (think ramekins) as an appetizer to a light entrée like sole meunière, another spring favorite. To garnish, you can add fresh herbs like chopped chives, thyme, or a drizzle of olive oil on top.
Leek Soup Recipe
A creamy, French potato and leek soup.
- 1 stalk of leek see note
- 1 large russet potato
- 1 tbsp unsalted butter
- 1 medium clove of garlic minced
- 1 sprig of thyme stem removed, leaves only
- 1 (14.5 oz) can of reduced sodium chicken stock or vegetable stock
- 3/4 cup water or more (see note)
- pinch of salt to taste
- pinch of freshly ground pepper
- 1-2 tbsp heavy cream
Prepare your leek by first cutting the leek in half, lengthwise, to produce two long halves. Rinse each half under cool running water, pulling each leaf back to make sure you rinse off any sand or grit hidden between the leaves.
Once your leek is cleaned, remove the root end of the leek as well as the very dark tips of the leek (the lime green parts are OK). Chop up the leek halves into small slices.
Rinse and peel your potato, then cut up into small 1" - 1 1/2" chunks. Temporarily set aside.
Melt the butter in a medium saucepan over medium heat. Add the garlic in and sauté for less than 30 seconds, just until fragrant.
Add the leeks and fresh thyme leaves and sauté for a couple of minutes. Add in the potatoes followed by the chicken stock and water. The potatoes and leeks should be fully immersed in liquid. If they're not, add more water until they are. Turn up the heat to high and bring the soup to a boil.
Once boiling, lower the heat to medium-low and cover the saucepan. The soup should be just simmering now - cook for 15 minutes or until the potatoes are tender. Check on your soup periodically to make sure it has enough liquid in the pot. If your potatoes still need time to cook and the liquid is very low in the pot, add just a little bit more water, as needed.
Transfer the contents of the saucepan to a food processor. Purée until smooth and creamy. Transfer back into the saucepan.
Heat the soup back over low heat over the stove. Add a pinch of salt and pepper, then taste test for salt. Add more as needed.
If using heavy cream, pour in the cream and stir to blend in. Cook the soup for another minute over the stove, then serve in small ramekins or other equally small bowls.
When shopping for leeks, choose leeks that are mostly white and lime green. The dark green tips of the leeks need to be removed so it's best to find leeks where the dark green parts are minimal.
Depending on the size of your saucepan, you may need more or less water in order for your leeks and potatoes to be fully immersed in liquid, so adjust as needed.