Caramelized Onion and Potato Soup (2024)

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).

1. Thinly slice the onions to ¼″ wide.
2. 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.
3. 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.
4. Add the garlic and saute 1 minute, stirring constantly.
5. Add the potatoes and pour in the broth. Season with salt and pepper, then add fresh thyme, fresh rosemary, and a bay leaf.
6. Bring the broth to a simmer, then cover and cook 20 minutes, or until the potatoes are very tender.
7. 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.
8. Ladle soup into bowls, then drizzle with olive oil and sprinkle with fresh thyme. Serve warm, right away. Enjoy!

Chef’s Tips!

• 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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Recipe