If ever there was a soup worthy of a fancy dinner party, this creamy roasted Cauliflower Potato Leek Soup is it. Despite looking and tasting like something you’d get at an expensive French restaurant, it’s made with only 10 basic ingredients in just 45 minutes. Effortless, inexpensive elegance for the win!
I don’t know about you, but I’m a sucker for soup of all sorts. Whether it's puréed or chunky, creamy or brothy, vegetarian or meaty, if you put a bowl of soup in front of me, I’ll happily wolf it down. In fact, soup season is a year-round phenomenon at our house!
For as long as I can remember, creamy potato leek soup has always been in my Top 10 list. I even made it for my first dinner party when I was just 10 years old! (Back then I added WAY too much white pepper, but it was my first rodeo. 🤷♀️)
While you can’t really improve on a French classic such as this, I’ve swapped out half the potatoes in favor of roasted cauliflower for an added nutritional boost. And y’all? It tastes SO GOOD. Boasting a rich, creamy consistency and a deliciously complex flavor without any fuss, this cauliflower leek potato soup is a recipe you’ll want to make again and again.
Add a drizzle of cream, a handful of crushed kettle chips, and some crispy frizzled leeks for texture and visual appeal, and BOOM! You’ll have yourself a bowl that would even impress Martha Stewart. Don't forget a crusty sourdough ciabatta bun to sop up every last drop of creamy goodness.
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Why You’ll Love This Leek Potato Cauliflower Soup Recipe
While soup is often billed as a humble comfort food, some recipes transcend that cozy classification to become haute cuisine. This potato leek cauliflower soup is one of them. Despite being made with just 10 basic ingredients, it has a depth of flavor that is astonishing.
Aside from being rich, creamy, and lick-the-bowl delicious, this yummy soup recipe is:
- Quick & Simple - All you need is 45 minutes from start to table.
- Inexpensive & Elegant - This potato cauliflower leek soup has a flavor that’s so much more than the sum of its parts. And, while it’s lovely on its own with nothing more than a few frizzled leeks on top, some creative garnishing with potato chips and a quick swirl of cream or dollop of yogurt takes it into black tie territory.
- Adaptable - Don’t you love a good culinary chameleon? This recipe for roasted cauliflower, leek, and potato soup is naturally vegetarian, but can easily be made vegan. You’re also welcome to add a boost of protein by swapping in chicken bone broth for the veggie stock. Can’t find leeks at your local store? Not to worry — I’ve got you covered with several delicious alternatives. Read on below for plenty of easy variations!
- Meal-Prep Friendly - Whip up a batch on the weekend and enjoy it all week long. I’ve also included simple instructions for freezing it for up to 3 months in case you want to bring it to a soup swap or to stock your freezer.
Ingredients & Substitutions
As promised, you only need a few simple ingredients to make this leek, cauliflower, and potato soup. Here’s what to grab:
- Cauliflower - I like to grab a 2-pound bag of florets from Costco since they’re already prepped and ready to go, plus are typically less expensive than buying whole heads from most other stores. That said, feel free to use whole cauliflower. To get the most bang for your buck, peel and chop the stems and roughly chop the leaves — they’re all edible! You’re also welcome to use frozen cauliflower florets; they roast just as well as fresh.
- Garlic - You’ll need whole cloves to get the proper roasted flavor we’re after. I only used a few to let the flavor of the leeks hold the spotlight, but feel free to add more to taste.
- Neutral Oil - Whether you use avocado, canola, grapeseed, corn, peanut, or vegetable oil makes no difference. Melted ghee also works! You just need some kind of fat with a high enough smoke point to roast the veggies at 450F.
- Butter - Using just a touch of butter adds lovely richness. Vegan butter can also be used.
- Leeks - If possible, get whole leeks (rather than the trimmed ones from Trader Joe’s). Not only do trimmed leeks often cut off more of the useful parts than needed which contributes to waste and higher prices, but even the tough dark green tops can be saved in a gallon bag in the freezer for a simple no-waste vegetable broth. Can’t find leeks? I’ve got you covered under the Optional Variations section below.
- Yukon Gold Potatoes - Yukons are the ideal all-purpose potato. They’re starchier than most wax potatoes, have a thin skin that doesn’t require peeling, and a creamy, dense texture that’s lovely in this soup.
- Vegetable Broth - I suggest using either Better Than Bouillon paste or homemade veggie broth. I recently used the leftover bean cooking liquid from my cheesy white bean tomato bake plus some BTB paste with hot water, and it was amazing!
- Cream - Optional, for added richness. You are welcome to use half-n-half or swap in the vegan cream alternative of your choice.
- Crushed Potato Chips - Optional, but delicious as a garnish for some added texture. Plus, it’s a great way to use up the crumbs at the bottom of the bag! I prefer using whole kettle chips, but feel free to use whatever you have on hand. My photographer used the tail-end of some tortilla chips she had and said it was yummy. I also typically stick to plain potato chips here, but flavored options like sour cream and onion or salt and vinegar would also be very welcome.
- Kosher Salt & Cracked Black Pepper - For basic seasoning, to taste.
How To Make Cauliflower Potato Leek Soup
This recipe for leek, potato, and cauliflower soup comes together in a snap. Here’s how:
Step 1: Roast Cauliflower & Garlic. Preheat oven to 450F. Line sheet pan with parchment paper. Toss cauliflower and garlic cloves with oil, then season with 1 teaspoon kosher salt. Roast in the preheated oven for 20-25 minutes, shaking once halfway. The cauliflower should be golden with a few charred spots and the garlic cloves should be soft.
Step 2: Sauté Leeks. Before beginning, soak the leeks well, then drain. While the cauliflower roasts, melt the butter in Dutch oven over medium heat. Add whites and pale green parts of the circular sliced leeks plus a large pinch of kosher salt. Sauté until softening and a fond is beginning to form on the bottom of the pan, about 8-10 minutes.
Step 3: Simmer. Add cubed potatoes and sauté for 1-2 minutes, then add the vegetable broth. Simmer over medium heat for about 15-20 minutes while cauliflower roasts.
Step 4: Add Roasted Cauliflower & Garlic to the pot. Continue to simmer over medium heat until potatoes are fork-tender.
Step 5: Blend the soup using an immersion blender (or working in batches with a regular blender). Add cream if using, then season again with kosher salt and pepper to taste.
Step 6: Air Fry Frizzled Leeks. While the soup base is simmering, dry the thin, vertically sliced medium greens of the leeks. Toss with 1 teaspoon of oil and big pinch of kosher salt. Spread out in the basket of your air fryer in a single layer. Air fry the leeks at 350F for 8-12 minutes, until most are browned and crispy.
Step 7: Plate & Garnish. Scoop blended soup into bowls. Garnish with a thin drizzle of cream (if using), a handful of lightly crushed potato chips, and frizzled leeks. Enjoy!
Optional Variations & Dietary Adjustments
Can’t find an ingredient, or need to make some dietary adaptations? Not to worry. This potato, cauliflower, and leek soup recipe is very flexible. Here are some easy variations to try:
- Dairy-Free/Vegan - Swap in vegan butter and either omit the cream or use vegan whipping cream or vegan half-n-half to make a vegan cauliflower potato soup.
- Leek-Free - As much as I love these mildly flavored alliums, they’re not always so easy to get your hands on. If that’s the case, you still have options! Here are some of my favorites:
- Roasted Garlic - The nutty, buttery flavor of roasted garlic is perfect for paring with potatoes and cauliflower. Grab a whole head (or two!) of garlic, slice off the pointy top enough to expose all the cloves at least a little bit, drizzle with about a teaspoon of oil, season with a pinch of salt, then wrap it all up in tin foil. Roast in the oven alongside the cauliflower, adding 5-10 extra minutes to the cook time as needed to make the garlic soft enough to squish out of the papery skin.
- Shallots - These pretty little beauties are a near-perfect swap for leeks. You’ll want about 2-3 shallots per leek, depending on how big they are.
- Scallions - Green onions don’t just look like mini leeks, they kind of taste like them too! To frizzle them, slice them into roughly 2-inch pieces, then halve and quarter them vertically to create matchsticks and separate the layers.
- Onions - Sweet onions, yellow onions, or red onions will all do the trick.
- Swap the frizzled leek garnish for crispy fried onions (like the kind you put on green bean casserole). You can also frizzle green onion, regular onion, or shallot slices in the air fryer instead. Alternatively, roast or air fry some tiny cauliflower florets for texture.
- Protein Boost - One of my favorite hacks for adding extra heft and protein to just about anything (including mashed potatoes!) is by swapping in chicken bone broth in place of regular veggie or chicken broth.
Recipe Success Tips
- Use what you've got. I like plain kettle chips, but sour cream and onion or salt and vinegar are both tasty too. My photographer used the tail end of her tortilla chips and said it was good, so you do you!
- Soak the leeks well. Because of the way leeks are shaped, dirt gets down between just about every layer. I suggest slicing the leeks first, then soaking them in a bowl of water for about 15 minutes, agitating them every so often to move them around. Drain them, rinse thoroughly, and use your fingers to separate the layers into individual rings. Repeat the soaking process as needed to remove all the dirt.
- If you’re using a head of cauliflower, use the WHOLE head! The leaves can be roughly chopped, and the stems can be peeled of any tough skin before chopping into floret-sized pieces. Roast these parts alongside the florets to get the most bang for your buck.
- Use parchment paper. Not only is it great for easy cleanup, it also makes it super easy to add all the cauliflower and garlic to the pot. I like to lift the parchment by the corners and fold it into a quasi-taco, then tilt the whole shebang to pour the contents into the pot with minimal splashing.
- The amount of added salt needed will depend on your veggie broth. If your broth is already seasoned, you’ll need less. If it’s a low- or no-sodium vegetable broth, you’ll need more.
- There’s no need to peel Yukon Gold potatoes for this roasted cauliflower potato soup recipe; they blend in beautifully. Less work + more nutrients = Yay!
- If you want to freeze it, don’t add the cream. You can always add it when you heat it up, but if you add it before freezing, the soup is liable to break.
FAQs
Sure thing! Simply swap in vegan butter and either omit the cream or use an unsweetened vegan alternative (e.g. cashew cream or vegan whipping cream).
There are a few different versions of potato leek soup I know of that originated in Europe. Two are French — vichyssoise and potage Parmentier. The Welsh version is known as cawl cennin. While they are all slightly different, the base ingredients and puréed texture are similar across all three. This potato, leek, and cauliflower soup draws inspiration from all of them.
Yes, but you’ll need to make a few adjustments. First, don’t use butter — swap in olive oil. Second, don’t add the cream — you can add that when you heat it up, if you like. Also, note that homemade soups are not suitable for water bath canning, and will need to be pressure canned. For more information, this post by Simply Canning is very helpful.
Absolutely! You can easily roast veggies (including cauliflower) from frozen, no need to defrost them first.
If you’re using the proportions outlined in the recipe card, this cauliflower, potato, and leek soup should be nice and thick. That said, if you want it to be even thicker, you have a few options:
1. Add potato flakes. My personal favorite method for thickening this soup is by adding more potato! Not only is it gluten-free and allergen-friendly, but it also maintains the original flavor profile. I keep a box of plain, unflavored, 100% pure instant potato flakes on hand for just this reason. (They’re also great for making shortcut gnocchi, thickening gravy, and more!)
2. Add a potato starch slurry. Potato starch can be used in a 1-to-1 ratio for cornstarch in pretty much every application I can think of. Mix up about a tablespoon of potato starch with a few tablespoons of the liquid of your choice (water, broth, milk, cream), then stir the slurry into the puréed soup. Return the pot to heat and cook until the soup is visibly thickened.
3. Add a cornstarch slurry. Mix about a tablespoon of cornstarch with a few tablespoons of water, broth, milk, or cream, then add to the soup after you’ve puréed it. Set the pot back over medium heat, and cook for a few minutes until visibly thickened.
4. Add flour. You’re welcome to add a few tablespoons of all-purpose flour to the pot after the leeks have turned golden, but before adding the potatoes and broth. Cook for at least a minute or two, until the flour smells nutty, so the soup doesn’t taste chalky.
5. Simmer it longer. While we most often add things to thicken a soup, subtracting liquid is equally effective. Feel free to simmer the soup on low to medium-low heat, stirring occasionally, until enough liquid has evaporated for the soup to reach your desired consistency.
More Quick & Easy Soup Recipes
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Cauliflower Potato Leek Soup
Equipment
- Dutch Oven or large pot
- Salad Spinner or bowl, colander, and clean kitchen towel
- Immersion Blender or blender
- Air Fryer optional
Ingredients
- 2 pounds Cauliflower broken into florets; if using the whole head, stems peeled and chopped, leaves roughly chopped
- 4-6 cloves Garlic whole or sliced vertically in half (hot dog)
- 2-3 tablespoon Neutral Oil, divided e.g. avocado, canola, grapeseed
- 2 teaspoon Kosher Salt divided, plus more to taste
- 1 tablespoon Butter
- 2 large Leeks well soaked and drained, whites and pale greens sliced into rounds, medium greens sliced vertically into thin sticks
- 2 pounds Yukon Gold Potatoes cut into 1" pieces, no need to peel
- 8 Cups Vegetable Broth e.g. Better Than Bouillon or homemade
- ½ Cup Cream or half-n-half; optional
- Cracked Black Pepper to taste
- 1-2 Cups Lightly Crushed Kettle Potato Chips optional, for garnish.
Instructions
Roast Cauliflower & Garlic
- Preheat oven to 450F. Line sheet pan with parchment paper.
- Toss cauliflower and garlic cloves with oil, then season with 1 teaspoon kosher salt.
- Roast for 20-25 minutes, shaking once halfway. Cauliflower should be golden and garlic soft.
Make Soup Base
- While the cauliflower roasts, melt butter in Dutch oven over medium heat. Add whites and pale green parts of the leeks plus a large pinch of kosher salt. Sauté until softening and a fond is beginning to form on the bottom of the pan, about 8-10 minutes.
- Add cubed potatoes and sauté for 1-2 minutes, then add the vegetable broth. Simmer over medium heat for about 15-20 minutes while cauliflower roasts.
- Add roasted cauliflower and garlic to the pot. Continue to simmer over medium heat until potatoes are fork tender.
- Blend the soup using an immersion blender (or working in batches with a regular blender). Add cream if using, then season again with kosher salt and pepper to taste.
Frizzled Leeks
- While the soup base is simmering, dry the thin, vertically sliced medium greens of the leeks. Toss with 1 teaspoon of oil and big pinch of kosher salt. Spread out in the basket of your air fryer in a single layer.
- Air fry the leeks at 350F for 8-12 minutes, until most are browned and crispy.
Plate & Garnish
- Scoop blended soup into bowls. Garnish with a thin drizzle of cream (if using), a handful of crushed potato chips, and frizzled leeks. Enjoy!
Notes
- Use what you've got. I like plain kettle chips, but sour cream and onion or salt and vinegar are both tasty too. My photographer used the tail end of her tortilla chips and said it was good, so you do you!
- Soak the leeks well. Because of the way leeks are shaped, dirt gets down between just about every layer. I suggest slicing the leeks first, then soaking them in a bowl of water for about 15 minutes, agitating them every so often to move them around. Drain them, rinse thoroughly, and use your fingers to separate the layers. Repeat the soaking process as needed to remove all the dirt. Also, make sure to keep the rounds separate from the matchstick slices, soaking them separately to make life easier.
- If you’re using a head of cauliflower, use the WHOLE head! The leaves can be roughly chopped, and the stems can be peeled of any tough skin before chopping into floret-sized pieces. Roast these parts alongside the florets to get the most bang for your buck.
- Use parchment paper. Not only is it great for easy cleanup, it also makes it super easy to add all the cauliflower and garlic to the pot. I like to lift the parchment by the corners and fold it into a quasi-taco, then tilt the whole shebang to pour the contents into the pot with minimal splashing.
- The amount of added salt needed will depend on your veggie broth. If your broth is already seasoned, you’ll need less. If it’s a low- or no-sodium vegetable broth, you’ll need more.
- There’s no need to peel Yukon Gold potatoes for this roasted cauliflower potato soup recipe; they blend in beautifully. Less work + more nutrients = Yay!
- If you want to freeze it, don’t add the cream. You can always add it when you heat it up, but if you add it before freezing, the soup is liable to break.
- Dairy-Free/Vegan - Swap in vegan butter and either omit the cream or use vegan whipping cream or vegan half-n-half to make a vegan cauliflower potato soup.
- Leek-Free - As much as I love these mildly flavored alliums, they’re not always so easy to get your hands on. If that’s the case, you still have options! Here are some of my favorites:
- Roasted Garlic - The nutty, buttery flavor of roasted garlic is perfect for paring with potatoes and cauliflower. Grab a whole head (or two!) of garlic, slice off the pointy top enough to expose all the cloves at least a little bit, drizzle with about a teaspoon of oil, season with a pinch of salt, then wrap it all up in tinfoil. Roast in the oven alongside the cauliflower, adding 5-10 extra minutes to the cook time as needed to make the garlic soft enough to squish out of the papery skin.
- Shallots - These pretty little beauties are a near perfect swap for leeks. You’ll want about 2-3 shallots per leek, depending on how big they are.
- Scallions - Green onions don’t just look like mini leeks, they kind of taste like them too! To frizzle them, slice them into roughly 2-inch pieces, then halve and quarter them vertically to create matchsticks and separate the layers.
- Onions - Sweet onions, yellow onions, or red onions will all do the trick.
- Swap the frizzled leek garnish for crispy fried onions (like the kind you put on green bean casserole). You can also frizzle green onion, regular onion, or shallot slices in the air fryer instead. Alternatively, roast or air fry some tiny cauliflower florets for texture.
- Protein Boost - One of my favorite hacks for adding extra heft and protein to just about anything (including mashed potatoes!) is by swapping in chicken bone broth in place of regular veggie or chicken broth.
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