Nourishing and tasty soups are made for chilly winter days. This super flavorful and velvety soup is prepared with only 5 ingredients, however, it has all the flavors and the nutrients that a fabulous soup should have. Roasted cauliflower and leek make a tasty base. A carefully selected seasoning perfects the flavors. The icing on the cake — so to say — is whipped cream that is added in the end to make the soup rich, creamy, and airy. Are you ready to sink your spoon into this sublime soup?
How to make this 5-ingredient Roasted Cauliflower and Leek Soup
Even this dish has only 5 ingredients, it’s good to reserve some time for preparing it — it’s really worth it as the result is so tasty that you can certainly serve the soup for your best guests (like I did!).
As for the preparation process: First, you’ll roast the cauliflower and the leek, then cook with broth and thyme, puree until smooth, and finally mix in some whipped cream to perfect the soup. That’s it.
Serve the soup immediately, although it stores well in the fridge and also freezes well. That said, it’s best to store the soup without whipped cream and add the cream right before serving — naturally after heating the soup.
But, without further ado, let’s take a look at how to prepare this tasty and nourishing keto-friendly soup:
Take a medium (1 1/2 lbs = 680 g) cauliflower head.
Cut it into bite-sized chunks.
Place the chunks on a parchment paper-lined baking sheet next to each other. Leave some space for the leek.
Next, take a small leek (about 8 oz = 230 g). Clean it thoroughly as it loves to gather some soil and sand inside. Cut the leek into three pieces.
Slice the leek lengthwise into halves.
Place the leek also on the baking sheet.
Roast at 400 °F (200 °C) for 30 minutes, until the veggies have some color on top. Don’t let burn!
Transfer (carefully!) the hot veggies into a medium saucepan. The easiest is to grab the parchment paper from the corners and slide the hot veggies into the saucepan. Like this:
Here we go.
Add 1 1/2 cups (350 ml) bone broth or chicken broth…
…and 1 teaspoon dried thyme.
Mix well. Bring to a boil over high heat.
Once boiling, turn the heat to medium-low. Let simmer with lid slightly ajar for about 30 minutes, or until the cauliflower and the leek are completely soft and tender.
Puree with an immersion blender or in a regular blender…
Next, you’ll need 1/2 cup (120 ml) heavy cream.
Whip the cream until soft peaks form.
Fold the whipped cream in the hot soup.
Serve immediately, decorated with fresh herbs.
How I came up with this easy keto soup recipe
If you have been following me, you might realize that this Roasted Cauliflower and Leek Soup recipe is a combination of several of my recipes — or actually, I’ve picked the best ideas of my existing soup recipes. Namely, I’ve got the idea to use roasted cauliflower from this recipe, leek from this recipe, and whipped cream from this recipe.
Well, but coming up with this Roasted Cauliflower and Leek Soup wasn’t that straightforward. I had written down a plan to make a soup with roasted cauliflower, however, I didn’t have any ideas for other ingredients. Maybe broth as liquid? But, those two ingredients, roasted cauliflower and broth, wouldn’t have brought enough flavor, so I needed something fancier, but not too fancy, just something ordinary but tasty.
I decided to add a roasted garlic bulb to my soup. Roasted garlic had worked wonders in one of my soup recipes and lent delicious flavor. As I also desired a creamy and rich soup, I chose to add some heavy cream.
I also need some seasonings and originally wanted to add dried thyme, but since I did the first soup experiment in our summer house where I didn’t have thyme, I picked oregano from the limited summer house pantry and decided to add it. I could always buy some thyme when I next time went grocery shopping, I thought, but oregano sounded like a nice emergency option to replace thyme.
For the first experiment, I roasted cauliflower chunks and a garlic bulb in the oven. I transferred the roasted cauliflower to a saucepan and also squeezed the soft contents of the garlic bulb in. Next, I added water (as I didn’t have any bone broth or chicken broth!), heavy cream, and dried oregano.
I cooked the soup for about 30 minutes, until the cauliflower had turned completely soft. I seasoned the soup with salt and pureed it until smooth. Excitedly, I took a spoonful of soup and put it into my mouth.
To my disappointment, the soup tasted totally weird! I don’t know which of the ingredients was ruining my ultimate soup experience, the water I used instead of broth, or the oregano I used instead of thyme — or maybe simply cooking the cream? Or maybe all those together? In any case, I wasn’t happy at all with my soup.
Interestingly enough, the flavor reminded me of a dish my mom used to make when I was a kid. I couldn’t recall the actual dish, I just remembered the flavor. However, my experiment was hardly edible, whereas the dish that my mom made tasted good.
I certainly didn’t want to post that inferior soup recipe here on my blog, so I went back to the drawing board and started ideating. Well, I undoubtedly wanted to use roasted cauliflower, broth, and heavy cream, but what would be the two remaining ingredients?
I suddenly realized leek is not only the onion variety that is lowest in carbs but also a super tasty ingredient in soups. So, I decided to add one small leek to my soup. My first idea wasn’t to roast the leek, but cook raw leek with the roasted cauliflower, however, I ended up roasting the leek together with cauliflower. To be honest, I haven’t roasted leek before, but I decided to give it a try. Maybe roasting also deepens the flavors of leek?
For the seasoning, I was sticking to dried thyme. For a moment, I was thinking of Cajun seasoning, but opted for thyme anyway — now when I had bought some when going to the town for grocery shopping.
And since I wasn’t happy with the cooked cream, I remembered my close-to-ten-year-old pumpkin soup recipe that used whipped cream which was added in the end. The whipped cream ultimately perfected the pumpkin soup, so maybe it would work well in this velvety pureed soup, too?
As I had a very busy week, I didn’t do any more experiments but was trusting my gut feeling and shot the photos while doing my freshly-planned soup recipe with 1 medium head roasted cauliflower, 1 small leek, 1 1/2 cups (350 ml) chicken broth, 1 teaspoon dried thyme, and 1/2 cup (120 ml) heavy cream that I had whipped until soft peaks formed.
The soup turned out unbelievably flavorful and enormously rich. It was just a perfect dish for freezing temperatures and to be enjoyed as a light but satisfying meal. It was an excellent idea to roast the leek as well as the flavor indeed became deeper and more concentrated. Wonderful! I was super happy with the soup — I bet you will be, too!
Here’s the recipe for you to enjoy:
- 1 medium head (1 1/2 lbs = 680 g) cauliflower
- 1 small (about 8 oz = 230 g) leek
- 1 1/2 cups = 350 ml bone broth or chicken broth
- 1 teaspoon dried thyme
- 1/2 cup = 120 ml heavy cream
1. Preheat the oven to 400 °F (200 °C).
2. Chop the cauliflower into bite-sized chunks. Spread the chunks on a parchment paper-lined baking sheet.
3. Clean the leek and chop into three pieces. Slice the pieces lengthwise into halves. Place the halves on the baking sheet with the cauliflower.
4. Roast until the veggies get some color on top, about 30 minutes. Don’t let burn!
5. Place the roasted cauliflower, leek, broth, and the thyme into a medium saucepan. Bring to a boil over high heat.
6. Once boiling, turn the heat to medium-low. Let simmer with lid slightly ajar for about 30 minutes, or until the cauliflower and the leek are completely soft and tender.
7. Puree with an immersion blender or in a regular blender until smooth.
8. Whip the cream until soft peaks form.
10. Fold the whipped cream in the hot soup. Serve immediately, decorated with fresh herbs.
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|Per serving if 4 servings in total
Tips for variations
Before roasting the cauliflower chunks and the leek, you can toss them in olive oil, salt, and pepper. Actually, you can add the thyme in this phase as well. Don’t add thyme, though, if you are not using oil as thyme just burns and gets pungent flavor. With oil, things are totally different, and thyme stands heat well.
Even though I recommend thyme to season this soup, you can certainly use other seasonings. The Cajun seasoning I was thinking for a moment would definitely be a great match. Other suitable seasonings for this soup are Italian herb mix, rosemary, basil, parsley, marjoram, tarragon, and even mint. As you can guess, I don’t recommend oregano for this dish — even oregano is my ultimately favorite herb!
You can replace leek with yellow onion or shallot, however, they are higher in carbs. On the other hand, they are sharper in flavor, so you can use about half of the amount of leek — which nicely reduces the carb count.
Feel free to add some garlic as well, however, I don’t recommend roasting it, just adding a couple of cloves of crushed garlic before cooking the soup. Alternatively, and for a stronger garlic flavor, you can add one or two crushed garlic cloves to the soup right before pureeing it.
For a dairy-free option, add coconut cream instead of dairy cream. As coconut cream doesn’t whip, you can mix it in as-is.
So, this week, I came to our summer house to escape the noise and fuss of the town life. I’ve longed to spend some time in nature, far away from the commotion and general hassle. The summer house is located in the middle of nowhere, so it’s a perfect place to escape and calm down.
However, things haven’t been that calm in my work-life. I have had a busy week working on Ketokamu projects and a keto course for the nutrition therapy school I graduated from and where I’m teaching now. I’m going to give a full-day course for the nutrition therapy students on Sunday, i.e., when I’m posting this blog post. It’s an intense day but certainly fun and fruitful!