Creamy Cauliflower Potato Leek Soup

This creamy, vegan cauliflower potato leek soup has only 5 ingredients, is ridiculously simple to make, and uses leeks in their entirety (yay to reducing food waste!).

Potato-leek soup is, of course, a staple of the winter soup canon. But have you tried adding cauliflower to the mix? Not only does this super vegetable contribute a wealth of nutrients, but it also makes for an earthy-sweet flavor and velvety texture.

This cauliflower potato leek soup is naturally creamy thanks to the magic of Yukon Gold potatoes. No cream, coconut milk, or cashews are needed here. Even more great news: the dairy-free soup calls for just 5 simple and cheap ingredients (well 8, if you count oil, salt, and pepper).

When developing this recipe, I made it a point to use up the entire leek – white and green parts. Many recipes will tell you to discard or find another use for the dark greens, while here, we turn them into a delicious soup garnish.

A Word on Leek Greens

As mentioned earlier, this recipe uses the entire leek: from white to dark green. A lot of recipes discard the dark greens and that’s just insane! Because they’re totally edible – albeit a bit more pungent and fibrous than their white counterparts. You should only discard any parts that are bruised/browned (I usually chop off just 1 to 2 inches from the bottom).

Here, I fry up the leek greens separately and use them as a garnish. If you’re feeling lazy, save them for later and make this white bean purée or this leek-pea pasta with them instead.

Key Ingredients + Substitutions

• Leeks: This flavorful vegetable belongs to the onion family and looks like a giant scallion. Flavorwise, it’s less pungent than a white onion and has an herby freshness to it. Leeks generally harbor dirt/sand between their layers so they have to be cleaned thoroughly before cooking; more details below.
• Potatoes: I recommend Yukon Golds for their waxy texture and sweet flavor. But regular Idaho potatoes would work, too.
• Cauliflower: I recommend fresh, but you can use frozen, if that’s what you already have.
• Broth: Use store-bought broth or DIY one from vegetable scraps. You can also use Yondu or Better Than Bouillon diluted in water.

How to Prep Leeks for Soup

Leeks are generally quite sandy and should be washed thoroughly before using. The best way to do it is in a salad spinner, but a large bowl of water will work, too. Once your leeks are chopped, add them to the spinner/bowl filled with water and swirl vigorously with your hands white separating the layers to release the dirt. Repeat the process with fresh water if your leeks seem extra dirty.

How to Make Cauliflower Potato Leek Soup

Find complete instructions with ingredient amounts in the recipe card below.

Step 1: Sauté the Leeks

Separate the white and light green parts, and clean them as detailed above. (Save the dark greens.) Cook the leeks with salt and oil until they’re soft and lightly golden, about 10 minutes. Then add garlic and sauté for 30 more seconds.

Step 2: Simmer the Soup

Add the potatoes, cauliflower, and broth to the pot. Cover with a lid and bring to a boil. Then reduce the heat to low and simmer gently until the vegetables are tender, about 20 minutes.

Step 3: Make the Garnish

Again, this is totally optional, but if you wanna use up the greens, make them into a crispy garnish while the soup is simmering. Chop and clean them, and cook them in a generous amount of oil until they’re dark brown and crispy, about 15 minutes. For optimal crispness, resist the urge to stir them too much during cooking.

Step 4: Purée the Soup

Using an immersion blender, puree the soup until completely smooth and creamy. You can use an upright blender, too, just be sure to read the safety notice in the recipe card below.

More Tips

If you wanna explore other crispy soup toppings, try shiitake bacon, spiced pumpkin seeds, or homemade croutons. New to the immersion blender? Make this creamy tomato-rice soup or vegan palak paneer next!