If Potato Onion Soup is another one of my healthy pureed soups that’s creamy without cream, then how is it so darn decadent? Maybe it has something to do with those sweet, soft caramelized onions that get blended with buttery Yukon gold potatoes for a velvety finish. This “creamy” soup is absolutely magical, and you’ve gotta taste it for yourself!
When you hear the phrase “potato soup,” you’re probably envisioning a go-big-or-go-home bowl of loaded baked potato soup with all the trimmings. Or maybe you’re thinking of something like our creamy pureed broccoli soup that uses potato to thicken the broth. But I’m thinking of something even simpler.
Potato onion soup. Kinda sounds like something you hear about your ancestors eating in the “old country” during times of famine. Just boil the hell out of some onions and potatoes and don’t bother draining the water when you’re done. Mmm mmm (not) good.
But I wouldn’t do you like that.
So instead, let’s see what you think about a velvety smooth pureed soup that’s decadent and buttery with notes of… oh my! What is that?? Is that… caramelized onion?? You bet your sweet onions it is. They’re not just for French onion soup.
Potatoes, on their own, can be fairly bland and uninspired. But they don’t need big, bold flavors to bring out their best – sometimes all you need is a ‘lil nudge. That’s why simple potato recipes like rosemary roasted potatoes or broccoli potato soup are so good.
Now, properly caramelizing onions ain’t quick, but it is easy. So if you love to cook (and you would not put up with my antics if we were not kindred spirits in our culinary ambitions) then consider this your lil nudge.
Tips for Caramelizing Onions
The bulk of the flavor in this recipe comes from the caramelized onions. It’s an investment, but a worthy one. Caramelizing onions takes time, patience, and moisture.
Keep the following tips in mind:
- Evenly slice the onions, but not too thin – about a ¼″ thick is perfect.
- Remember – sweet (Vidalia) onions will yield sweeter flavor.
- Butter is delicious, but also more susceptible to burning on its own – add a splash of olive oil.
- To properly caramelize onions, you have to cook them low and slow. Start with medium heat, but reduce if they start to burn around the edges.
- Add liquid to deglaze and lower the pan heat as needed – you can use water, broth, or wine.
- Stir the onions frequently, but not constantly, so they caramelized evenly.
- And once you think they’re done, cook ’em just a bit longer.
How to Make Potato Onion Soup
Potato Onion Soup is 100% worth the time it takes to caramelize the onions – they add buttery sweetness and so much flavor. This rich and nourishing pureed soup is a total comfort food, even though it’s creamy-without-the-cream. Naturally Whole30, paleo, gluten and grain free, and dairy free (if you swap the butter for ghee).
- Thinly slice the onions to ¼″ wide.
- Melt the butter in a dutch oven over medium heat, then add the onions and a pinch of salt; toss well to coat the onions in the butter.
- Saute over medium heat, stirring every 5 minutes or so. The onions will first soften, then brown, then caramelize. Keep the onions slightly moist and adjust the heat of the pot by adding 1-2 teaspoons of water, broth, or wine as needed, or if you notice the that the onions start to scald (burn). The onions are ready when they’re uniformly deep golden brown.
- Add the garlic and saute 1 minute, stirring constantly.
- Add the potatoes and pour in the broth. Season with salt and pepper, then add fresh thyme, fresh rosemary, and a bay leaf.
- Bring the broth to a simmer, then cover and cook 20 minutes, or until the potatoes are very tender.
- Remove the herbs stems and bay leaf, then puree with an immersion blender until very smooth. Add additional broth as needed if the soup is too thick.
- Ladle soup into bowls, then drizzle with olive oil and sprinkle with fresh thyme. Serve warm, right away. Enjoy!
- Caramelizing onions takes time and patience – you’ll need anywhere from 30-40 minutes. Know this going in!
- Use bone broth to add healthy fat, extra nutrients, and a velvety texture to the finished soup (thanks gelatin).
- Fresh herbs add so much flavor, but dried can work in a pinch. Use ½ teaspoon dried thyme and rosemary.
- Potatoes love salt. Add a pinch when caramelizing the onions, then season again while the soup simmers. Taste for seasoning after blending and adjust to taste. If the soup feels bland, it probably needs more salt!
- This is a very thick soup; scrape the sides and bottom of the pot with a rubber spatula once or twice while pureeing so you don’t miss any pieces of potato or onion. Thin to preference with additional water or broth.
- Skins or no skins? Chef’s choice! We like the skins on if using tender new potatoes. We peel the skins off mature potatoes, especially russet potatoes.
What to Serve with Potato Soup
- Bread. If you need to be fancy about it, make your own croutons to garnish potato onion soup.
- If you’re big on “meat and potatoes” then you can’t go wrong with rosemary steak. You can keep with this theme even if you prefer soup and a (steak) sandwich, or soup and a (steak) salad.
- Looking for lighter fare? Any leafy green salad with a little bit of bite and plenty of acidity will do! Try shredded brussels sprouts salad or crunchy butter lettuce salad.
- Pair it with poultry – but be sure to punch up the flavor with some acid. Balsamic chicken or one-pan apple cider chicken go great with creamy potato soup!
Storing and Freezing
Potato soup will last in the fridge for up to 5 days. It will thicken as it cools thanks to the starches – thin with broth as needed when reheating.
This soup will keep in the freezer for up to 6 months if properly stored in an air-tight container.
Did you make this potato and onion soup? I’d love to know how it turned out! Leave a comment and a rating below.
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- 2 tbsp butter, see Note 1
- 1 large vidalia onion, thinly sliced into ¼" slices (2.5 – 3 cups sliced)
- 2 cloves garlic, minced
- 24 oz yukon gold potatoes, diced into 1" cubes (4 heaping cups), see Note 2
- 4 cups broth, chicken bone broth preferred, but any broth will yield great results
- 1-2 cups water
- ¼ cup dry white wine, or additional broth
- 1 tsp kosher salt
- 1 tsp ground pepper
- 1 sprig fresh rosemary, plus more for garnish
- 1 sprig fresh thyme, plus more for garnish
- 1 bay leaf
- 1 tbsp fresh lemon juice
- 4 tbsp extra virgin olive oil, for garnish, optional
- Heat a dutch oven over medium heat; add the butter and oil heat until the butter melts then foams. Add the onions, season with a pinch of salt, then toss to coat in the fat.
- Saute the onions, stirring every 5 minutes or so, until the onions soften, then brown, then caramelize. If the pot gets too dry and the onions start to burn and/or stick, add a tablespoon of water or broth to deglaze the pan and keep the onions moist. I typically add up to ¼ cup of liquid during the caramelization process. The onions are done when they are uniformly deep, golden brown.
- Add the garlic and saute, stirring continuously, until the garlic is fragrant, about 1 minute.
- Deglaze the pot with the wine, stirring and scraping any browned bits. Cook until the wine is mostly absorbed, 3-5 minutes.
- Add the potatoes, broth, salt, and pepper, then give everything a good stir. Top with the fresh rosemary, fresh thyme, and bay leaf. Increase the heat to high and bring the liquid to a boil. Reduce to low and simmer until the potatoes are cooked through, about 20 minutes.
- Fish out the herbs stems and bay leaf, then add the lemon juice. Blend right in the pot with an immersion blender until smooth, or carefully transfer to a blender and blend until smooth (you may need to do this in batches). Add additional water to thin as needed. Once smooth, taste for seasoning and adjust with salt, pepper, and/or lemon juice until the flavor sings.
- Ladle the soup into bowls. Drizzle with olive oil and fresh herbs to taste, and serve right away. (see Note 3)
- Note 1. If you’re Whole30 or paleo, use ghee.
- Note 2. Feel free to keep on the skins, especially if using new/baby potatoes. Scrub well before chopping.
- Note 3. Garnish can make or break a soup. We love a drizzle of extra virgin olive oil – it’s sweet and tangy, and gives a nice contrast to the rich soup. You can also consider a dollop of heavy cream or sour cream, or skip entirely.