Instant Pot Potato Leek Soup with Horseradish Sour Cream

Embrace fall’s chilly weather with homemade Instant Pot Potato Leek Soup. Creamy, familiar and gently spiced with a piquant horseradish sour cream, you’ll love the cozy comfort of this easy potato soup.

I dove head-first into soup season last month, and haven’t yet come up for air. It’s still not quite fall weather here — we’re looking at upper 80s later this week … you know, in October, lol — so I’ve been using my pressure cooker to create and test new recipes, while keeping the kitchen nice and cool.

But, if you don’t own an Instant Pot, don’t worry – not all of my new recipes will be for the pressure cooker. I am a convert, though, despite not being a cooking-shortcut-gadget person. Although I have just a few Instant Pot recipes on the blog at this point, I’ve actually been putting it through its paces for almost two years now.

Honestly, I kept waiting for something to fail. Mush or goo or watered down … every time I lifted the lid, I expected to see a ruined meal.

But, it just didn’t happen. Instead, a new world opened up. Beans — from dried! — in about an hour. Perfect rice and quinoa. Rich, homemade vegetable stock in under an hour. “Baked” potatoes in way under an hour (and oh-em-gee, the baked sweet potatoes). Flawlessly peelable hard-boiled eggs. Homemade yogurt.

These multi-function units even have a saute function that let’s you brown meat and simmer aromatics, just like on the stove top, so you don’t have to lose out on flavor-building caramelization and Maillard reactions.

And, most unexpectedly (although rather obvious in hindsight, lol): the Instant Pot brought a return to summer cooking, because the kitchen just doesn’t heat up.

I started with a 6 quart model, and added a 3 quart earlier this year. I use the 6 quart for meal and soup preparations, but the 3 quart, with its small footprint, usually stays on the counter. We’re heading into a great time of year to purchase an Instant Pot, so if you’ve been considering one, now’s the time to start researching the model that’s right for you.

Now on to the soup! Leeks are probably my favorite aromatic vegetable. A relative of the onion, they have a milder flavor that’s a cross between a sweet onion and garlic. Just completely lovely.

Following Julia Child’s example with her famous potato leek soup, I’m using a lot of leeks here. Not to worry, though: they cook down beautifully and add just the right amount of yum to the soup without overwhelming it.

How to Prepare Leeks

Leeks grow in long stalks (rather than being bulb shaped, like the rest of their onion siblings), and need special cleaning before they’re ready to use. Not difficult, just extra cleaning.

Leeks have rings, just like onions, but the plant is not enclosed by protective skin. Rather, a leek’s leaves are extensions of the stalk, and dirt and muck can get right down into those rings (and into your food).

To clean a leek, trim off the root end, and all the dark green leaves. Slice the leek in half down its length, not quite all the way through, revealing the inner layers of the leek. Fan open the leeks layers under running water and rinse away the dirt within.

Reform the cylinder shape of the leek stalk, and you can now slice into very neat half-moons, which can be further chopped, if desired.

To preserve full, circular slices, you can, instead, trim the stalk of its root end and leaves, and immediately slice the leek into thin rings. Use a salad spinner to thoroughly rinse and dry the rings. Saute them up, and get that potato soup started!

I love potato soup. I love how mild it is, how flexible it is.

I love how my favorite food in the whole wild world — the humble potato — transforms into a carby, comforting meal that fills the tummy and gives a big soupy hug in the process. (And deep in the heart of winter, there’s nothing better than a soup hug!)

Potato leek soup has a gentle reputation as being somewhat of a bland concoction. Bland, but perfect, like a big bowl of plain, buttered pasta that hits the spot the way that only carbs can. But that doesn’t mean potato soup has to be boring.

That’s where horseradish sour cream comes in.

How to Make Horseradish Sour Cream

This is an old Alton Brown-inspired recipe from a long ago “Good Eats” episode. Sour cream’s tang is the perfect foil for horseradish’s piquant, sinus-energizing bite. And best of all, this is a super easy, whisk-it-up condiment that can be prepared in minutes.

• You can use full fat or lite sour cream for this recipe – it’s all good!
• Don’t hesitate to use prepared horseradish: it’s easy and readily available. If you have access to fresh horseradish, use a fine microplaner to grate the horseradish. You can follow the quantities in this recipe for both prepared and fresh.
• Don’t be shy about adding horseradish – remember, you’re not using the sour cream as a dip. You’re adding it to the soup, so the horseradish will be diluted, muted. I call for 1 tablespoon of prepared horseradish in the recipe, but I usually edge up to 2 when I make it for myself. I love the back bite of the horseradish in this potato leek soup.
• If you’d like to make a dairy-free version, use cashew cream as the base instead of dairy sour cream. You’ll love it, I promise! (Follow steps 1 and 3 of this recipe).
• You’ll notice that my recipe below calls for you to temper the sour cream before adding it to the soup. I highly recommend this, because sour cream tends to “break” in hot liquids, resulting in unattractive white speckles spread throughout the soup. Although tempering means another bowl to wash, the process is quick and easy, and will keep your soup looking flawless.
• If you’d like to embellish your soup with hearts as I’ve done in the photos (this works best on thick versions of the soup, see below): whisk a small bit of the sour cream until very loose and creamy. Use a small spoon to place three big drops of sour cream on top of the soup, about an inch apart. Use a thin-bladed knife (like a paring knife or steak knife) and draw a straight line through the center of each of the three dots, in one stroke. Wipe the blade clean in between bowls. I do love me some SoupArt!

Tips for Making the Best Potato Leek Soup

Never forget that texture is a quality all its own in soup-making. Is a clear broth your soup thang? Or perhaps hearty chunks of vegetables? Or do you prefer your soups smooth and creamy?

My answer is … Yes! Lol. I love them all.

But for my Instant Pot Potato Leek Soup, I’m going to go with a compromise: I don’t want the soup perfectly smooth and creamy; nor do I want it brothy and chunky. Instead, my preferred preparation is a sort of applesauce texture, where there’s small, very tender chunks of potatoes in the soup. Perfection!

Here are some tips for getting just the texture you want:

• Chunky/brothy: chop the potatoes into smaller cubes than you normally would – 1/2″ to 3/4″ or so. When the soup finishes cooking, you don’t need to do anything, other than stir … and dig in.
• Chunky/smooth: a.k.a. Karen’s Way, lol. When the soup finishes cooking, use an immersion blender and, working very slowly, move your way through the soup in short bursts with the wand. Stop frequently and scoop up a spoonful to check the texture (the immersion blender can easily mask a soup that’s actually gone too smooth and creamy. Remember: you can always continue blending, but you can’t rechunkify a too-smooth soup.). I look for a rough applesauce appearance: very small chunks in a creamy, opaque broth.
• Perfectly smooth: When the soup finishes cooking, use an immersion blender to completely smooth out the soup, or transfer the soup in batches to a regular or high-speed blender. A standalone blender will make a much smoother result, although an immersion blender has easier cleanup.

Potato leek soup is the perfect soup for the Instant Pot, so if you’re looking for an easy, weeknight soup for pressure cooking, I hope you’ll give this one a try!

Karen xo

Print Recipe

5 from 2 votes

Instant Pot Potato Leek Soup with Horseradish Sour Cream

Creamy, savory potato soup made in the Instant Pot, and flavor-boosted with horseradish sour cream.

Course: Soup

Cuisine: American

Keyword: potato leek soup

Author: Karen Gibson

Ingredients

for the soup:

• 1 tablespoon olive oil
• 2 slices thick cut hickory bacon, chopped
• 3 cups chopped leeks, 2 to 3 large leek stalks, white and light green parts only
• 1 1/2 pounds russet potatoes, scrubbed, peeled and sliced into big chunks
• 3 cups vegetable broth
• 4 stems fresh thyme
• 2 bay leaves
• kosher salt
• freshly ground black pepper
• lemon juice

for the sour cream:

• 1/2 cup sour cream
• 1 tablespoon prepared horseradish
• 1 teaspoon dijon mustard
• pinch of salt

optional toppings:

• reserved bacon bits
• reserved horseradish sour cream
• snipped chives or green onions sliced on the bias
• grated cheddar cheese

Instructions

For the soup:

• Turn on the Saute function on your Instant Pot. Add the olive oil. When the oil begins to shimmer (the Instant Pot might not yet read "Hot" - that's okay), add the bacon. Cook the bacon until crispy, and then remove to a paper-towel-lined plate. Reserve for garnish.
• Add the leeks and turn off the unit*. Saute the leeks, stirring frequently until very soft, about 5 minutes. Add the potatoes, vegetable broth, 1 cup of water, plus the thyme and bay leaves.
• Secure the lid on the unit, and set the valve to Sealing.
• Press Manual pressure, and adjust the time to 6 minutes. Let the unit come to pressure, cook for the 6 minutes, and then natural release for 15 minutes. Cover valve with a towel and switch it to Venting to release the remaining pressure.

For the Sour Cream:

• While the soup cooks, prepare the sour cream. Add all of the ingredients to a small mixing bowl and whisk well. It will not be perfectly smooth because horseradish is coarse. Taste, and add a little more horseradish, if you'd like extra heat.

Finish the soup:

• Carefully remove the lid, opening it away from you, taking care to watch the drips from the lid. Remove the thyme stems and both bay leaves.
• Add a big pinch of salt to the soup, and use an immersion blender to blend the soup to your preferred texture. Go slowly and stop frequently to scoop out a spoonful of the soup to text for texture (sometimes it's hard to tell just by looking down into the pot).
• In a small mixing bowl, add 1/4 cup of the sour cream, and pour a 1/4 cup of the hot soup over it. Whisk immediately, until smooth. Stir into the soup. Taste the soup and add salt and pepper as necessary. Add splash of lemon juice to enhance the flavors, if necessary.
• Ladle into bowls, and serve with a dollop of the horseradish cream, and your choice of optional toppings.

Notes

*Instant Pots have a tendency to throw a "Burn" message when pressure cooking immediately follows using the saute function. Turning off the unit will cool the inner pot enough to avoid that message. Don't worry - it will still be plenty hot to saute the leeks!

Nutritional information, if shown, is provided as a courtesy only, and is not to be taken as medical information or advice. The nutritional values of your preparation of this recipe are impacted by several factors, including, but not limited to, the ingredient brands you use, any substitutions or measurement changes you make, and measuring accuracy.

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