🔑 Quick Answer: Potato leek soup is a French classic, made by sweating leeks in butter, simmering them with potatoes and herbs, then pureeing everything until smooth. Ours uses Yukon Golds and a splash of the starchy potato soaking water, so it turns silky in 80 minutes without any flour.
Potato leek soup is the reason I fell for French food in the first place. If you’ve hung around here at Salt & Wind for a bit, you’ve likely read that my love for France stems directly from my father marrying my French stepmother. My introduction to French food came through two recipes my stepmother, Michele, cooked on repeat: Potato Leek Soup and Cheese Soufflé.
Why Trust Us
I learned this soup from my French stepmother, Michele, long before I stepped into a professional kitchen. Then I trained in culinary arts at Le Cordon Bleu Paris and spent nearly twenty years as a professional recipe developer, and every recipe we publish is tested three to five times before it goes live.
I have been making this particular soup for decades. The one change I kept after all those rounds was adding shallots alongside the leeks, which gives the finished soup a depth leeks on their own don’t have.
On the travel side, we plan custom France itineraries for food-focused travelers all year, so this is also the recipe we hand to clients who want to cook classic French food at home before they go.
Best for: the cook who wants a real French recipe without a project attached to it, and anyone feeding a table of eight on a cold night.
Why You’ll Love This Recipe
The combination of buttery leeks, herbs, and a dash of cream means that Potato Leek soup is like the liquid version of a classic Baked Potato while airy clouds of egg and cheese are indisputably pure culinary magic.
When I moved to France to go to culinary school at Le Cordon Bleu Paris, I had a lot to learn in the kitchen but knew I could at the very least cook Michele’s classic recipes — Potato Leek Soup, Cheese Souffle, Leg Of Lamb, a Vinegar-y Salad, and an incredible Gratin — with the best of them. This is a recipe I’ve been cooking for decades and it’s a go-to in my household. Now, as a travel planner specializing in custom French travel itineraries for food lovers, I share this recipe with curious clients who want to cook classic French food.
Recipe Ingredients
Here is what each ingredient brings to this potato leek soup.
- Yukon Gold potatoes are the body of the soup, and their creamy flesh breaks down into a silky puree. Red Bliss or new potatoes work, though they stay a little more textured.
- Leeks are the flavor, and they give the soup a sweetness that onions cannot. Use only the white and pale green parts.
- Shallots add the depth that leeks alone miss. White or yellow onion covers for them in a pinch.
- Unsalted butter is what you sweat the alliums in, and it carries the flavor through the whole pot. Olive oil or vegan butter makes the soup plant-based.
- Garlic rounds out the allium base, so two cloves are plenty here.
- Bay leaf, thyme, and parsley keep the soup from tasting flat. Marjoram stands in for the thyme, and parsley stems do the job when you have no leaves.
- Low-sodium chicken or vegetable broth sets the soup’s boldness. Water works, vegetable broth keeps it vegetarian, and beef or veal broth makes it much richer.
- Heavy cream or crème fraîche is the finish that turns a good soup into a rich one, and you can leave it out.
- Nutmeg is the classic French seasoning for anything creamy, so grate it fresh right before serving.
- Chives and croutons give you the onion note and the crunch on top, and both are optional.
How To Make This Recipe
This soup comes together in five steps and one pot, and the whole thing takes 80 minutes.
- Prep the Potatoes: Dice the potatoes into half-inch cubes and keep them covered in water until you are ready to use them. You’ll use that starchy water later, so don’t throw it out.
- Sauté the Vegetables: Sauté the leeks, shallots, and garlic and season with salt and freshly ground black pepper.
- Simmer the Potatoes: Add the potatoes, bay leaf, thyme, parsley, and broth, and simmer until the potatoes are falling apart.
- Puree the Soup: Use an immersion blender or blender to puree the soup until smooth.
- Serve the Soup: Top the soup with any garnishes and serve.
Tips To Make The Best Potato Leek Soup
Classic French cooking has a reputation for being fussy and complicated, but that’s really only the case for high-end dining.
The more humble, homey recipes like this soup prove that a few ingredients and a little effort can result in a dish that makes you feel like you’re dining while floating down the Rhône, if only in your imagination. Over the years, I’ve learned a few key pointers that separate a good Potato Leek Soup from an exceptional one. Here are the top tips:
- Use Both Shallots and Leeks: The stars of this dish are leeks—a relative of the humble onion—and potatoes, so you could make this recipe with 100% leeks. But after making this recipe for years, I’ve found that combining the leeks with another onion-family ingredient, such as shallots (or white or yellow onions when in a pinch), adds depth to the final soup.
- Opt For Yukon Gold Potatoes: Leave it to the country that created potato gratin and fries to have numerous varieties of potatoes. We can’t often find French potatoes here in the United States, so we recommend Yukon Golds for soups— they have creamy flesh and delicate skin that adds nice texture to the final soup.
- Peeled Versus Unpeeled Potatoes: Traditionalists would have you peel the potatoes for a smoother texture and a more uniform color (ie no flecks of potato skin). Truth be told, I love the texture the skin of more delicate potatoes (like Yukon Gold) adds to this soup, so I recommend you leave them unpeeled.
- Add The Herbs You Have: The herbs you add while it simmers don’t need to be many, but they add a lot of flavor, so don’t forget them. At a minimum, add a bay leaf and, if you have them on hand, a few sprigs of fresh thyme or marjoram and a handful of parsley (even just the stems if that’s all you have) for subtle flavor.
- Make It More or Less Bold With Stock: You can make this potato leek soup with 100% water, but I prefer adding broth for more flavor. To keep it plant-based, add vegetable broth or water. If you are a carnivore, use chicken broth, or for a more intense flavor, veal or beef broth.
- Use The Potato Liquid As A Thickener: Make sure you DO NOT THROW OUT THE POTATO SOAKING WATER! This water is loaded with potato starch, which adds thickness to the soup and helps bring it together. It is not essential, but I think it helps make the soup more cohesive!
- Finish With Nutmeg And Cream: To make this soup healthier, you could use oil or vegan butter instead of standard butter, and you could skip the cream. However, this little bit of dairy really enhances the final dish’s flavor. Other ways to bring the flavor up? Add a few cranks of black pepper, freshly snipped chives or parsley, or freshly grated nutmeg just before serving!
The bottom line is that not all classic French food is complicated. This classic Potato Leek soup is simply buttery sautéed vegetables, pureed with herbs and a dash of cream, for one of the easiest and most satisfying soups ever!
How To Store Potato Leek Soup
This soup keeps for five days in an airtight container in the refrigerator and for three months in the freezer. Freeze it before you add the cream, because dairy separates when it thaws; then stir the cream in after reheating.
Reheat it gently over medium-low heat and stir as it warms rather than bringing it back to a hard boil. You can also dice the potatoes up to 24 hours ahead and keep them refrigerated in their soaking water, which you’ll use to thicken the soup anyway.
Variations On Potato Leek Soup
- Vichyssoise is the same soup served cold. Chill it thoroughly, thin it with a little more cream, and taste it again before serving, because cold food needs more salt than hot food.
- Make it plant-based by swapping olive oil or vegan butter for the butter, using vegetable broth, and skipping the cream. The potato starch thickens it either way.
- Make it richer by using beef or veal broth instead of chicken, which gives the soup a much deeper savory base.
What To Drink With This Recipe
Pour a village Chablis with this. Its high acidity cuts straight through the butter and the cream, and because village Chablis sees no oak, it leaves the sweet green flavor of the leeks alone.
Frequently Asked Questions
Potato leek soup is a French soup, soupe poireaux et pommes de terre, made from leeks sweated in butter and simmered with potatoes and herbs until everything falls apart, then pureed. It is one of the foundation soups of French home cooking, and the cold version of it is vichyssoise.
Yukon Golds are the best choice because their creamy flesh breaks down and thickens the soup. Red Bliss and new potatoes also work and leave a bit more texture. Russets turn grainy in a pureed soup, so skip them here.
You do not have to. Traditionalists peel them for a smoother texture and a uniform color, but the skin on a thin-skinned potato like a Yukon Gold adds texture we actually like. We leave ours unpeeled.
Yes, and it is better on day two. Make it through the puree step, cool it, and refrigerate it for up to five days or freeze it for up to three months. Stir in the cream after you reheat it, not before you store it.
Other Soup Recipes To Try
Here are a few of our other favorite soups to try:
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Classic Potato Leek Soup Recipe
Equipment
Ingredients
For The Potato Leek Soup:
- 2 pounds Yukon Gold potato (or substitute Red Bliss potatoes or new potatoes)
- 4 tablespoons unsalted butter
- 4 medium leeks cleaned and trimmed then thinly sliced into quarter moon pieces
- 4 medium shallots peeled and roots trimmed and discarded then minced
- 2 medium garlic cloves thinly sliced
- Kosher salt and Freshly ground black pepper
- 1 medium bay leaf
- 6 sprigs fresh thyme
- 1 handful fresh Italian parsley with tender stems, (optional)
- 1 quart low-sodium chicken or vegetable broth or beef broth
For Garnish:
- Drizzle heavy cream or crème fraîche, for garnish (optional)
- Freshly grated nutmeg for garnish (optional)
- Snipped fresh chives for garnish (optional)
- Handful croutons for garnish (optional)
Instructions
- Prepare The Potatoes: Cut the potatoes into a medium dice (about 1/2 inch cubes) then place in a nonreactive (metal or glass) mixing bowl and add enough water that the potatoes are just covered. Set aside until ready to use (you can cut the potatoes up to 24 hours in advance – keep stored in the water and refrigerated until ready to use).
- Saute The Leeks: Place the butter in a large Dutch oven or other heavy-bottomed pot and melt it over medium heat. Add the leeks, shallots, and garlic (if using), season generously with salt and pepper and stir to coat. Cook, stirring occasionally, until the leeks and shallots are soft and tender but don't let them get browned (lower the heat as needed to prevent browning).
- Add The Potatoes And Simmer: Remove the potatoes from their soaking water and reserve the soaking water (you'll use it later!). Add the diced potatoes to the pot along with the bay leaf, thyme, parsley (if using), and broth. You'll want to remove the herbs before blending so you can tie them all together with kitchen string (if you have it) to make it easier on yourself. Otherwise, just fish them out with the help of some tongs!Also, FYI, the vegetables should just barely be covered by the liquid. As needed add a touch more broth or water until the vegetables are just covered. Increase the heat to high and bring the mixture to a boil. As soon as the mixture boils, reduce the heat to low and simmer until the potatoes are so tender that they fall apart, about 25 to 35 minutes.
- Puree The Potato Leek Soup: Discard the bay leaf, thyme sprigs, and parsley stems. Add 2 cups of the reserved potato soaking water including any potato starch that accumulated in the bottom of the bowl as the potatoes soaked (if you don't have 2 cups of potato liquid add water to make up the difference). Then, using an immersion blender blend the soup until all the vegetables are broken down and the texture is consistent. You can blend it as much or little as you'd like at this point. Either just blend it until all the ingredients are combined but it is still quite textured (almost like a chowder) or keep blending it until it's more similar to a pureed soup.
- Finish The Potato Leek Soup: Taste the soup, stir in a large pinch of salt and lots of freshly ground black pepper and simmer the soup for 5 to 10 minutes more until everything has come together.
- Serve The Potato Leek Soup: You can serve the soup simply ladled in bowls with a crank of freshly ground black pepper. We like to add some croutons for crunch, some freshly snipped chives to emphasize the onion flavor, and a drizzle of cream to add a dash of richness. Also, if you like nutmeg, a little grate of it on the soup before serving is incredible!
