Chilled Fennel Soup is refreshing, fragrant, and perfect to enjoy on a warm day. The flavor profile is clean, cool and grassy and the smooth texture is accented by crunchy cubes of cucumber. It’s simple yet deeply satisfying. And it’s super easy and quick to make.
Why Chilled Fennel Soup is Great
This chilled fennel soup celebrates the mild fragrance of fennel in a soothing and straightforward way. Fennel is gently sauteed with a bit of sweet onion and then blended thoroughly with vegetable broth and then finished with bites of cucumber and a sprinkling of fennel and dill fronds.
I came up with this recipe because I have been getting into fennel more and more and I wanted something fitting for the hot summer days coming up.
After spending time in the sun and feeling overheated even after coming indoors, this soup was really relaxing and enjoyable to share with my family and today I’m excited to share it with you.
How to Make Chilled Fennel Soup
Slice The Fennel Thinly
It’s important to cut the fennel so that it will cook through and this generally means that you should slice it as thinly as possible.
The bulb is the toughest part and the part you need to slice most thinly. It’s also good to cut the stalks just as thin, but they are a little more watery so you don’t need to be as careful about it.
Set aside all the fronds, with some of the best-looking fronds (usually in the center closest to the bulb and the long, thin parts) in one batch for your garnish at the end, and the rest in another batch to be blended with the bulb, stalk, and onion.
Saute the Fennel and Onion Together
The main cooking step in this recipe is sauteing the fennel and onion until translucent and tender all the way thorough. I like to use olive oil for this as the grassiness plays nicely with the other flavors.
Saute the bulb and stalk of the fennel but not the fronds. This helps preserve the bright, grassy taste of the fronds, as well as the color.
Blend the Fennel and Onion
Pop the sauteed fennel and onion into the blender, add vegetable broth or stock (I used Better than Bouillon paste since it’s really convenient. I had to blend for 2-3 minutes to get the right consistency.
(This paste does have a darker color – if you want a light-colored final soup, you’ll want to use or make a light-colored broth and saute it over low heat to avoid browning.)
A Quick Note On Blenders
I used a Vitamix blender to develop this recipe and it created a very smooth soup. Other blenders may not blend as smoothly as shown here – the soup will still be tasty but the texture could be different.
Briefly Saute the Cucumber
This step may seem strange to you if you’re in the US, but sauteing cucumber is a nice way to concentrate the flavor and texture. It’s hard to describe, but the texture has a bouncier crunch than raw cucumber.
You want to saute it until it is just translucent. For me it only took a couple of minutes.
Chill, Garnish, and Serve
You’ll combine the blended soup and the sauteed cucumber cubes and let it cool and/or chill. I usually let it cool on the counter for a bit before putting it in the fridge for a couple hours. But I have a tip below if you want to get it ready faster.
When you serve the soup, you’ll want to garnish it with the reserved fennel fronds, some dill fronds, a touch of lemon zest, and a drizzle of olive oil. You don’t need to use all of these garnishes but they do add a bit of pop to this delightfully low-key soup.
A Tip to Speed Up the Process
If you’re using a concentrated vegetable broth paste (I like the “Better than Bouillon” brand), you can blend the fennel and onion with the full amount of broth paste but half the amount of water to dissolve the paste. Make up the rest of the volume with ice water, and then blend it all together.
Things to Keep in Mind When Cooking Chilled Fennel Soup
Pay Attention When Browning the Fennel
The best way to get a lovely caramelized flavor on the fennel and onion is to brown them when sauteing them. But this will also affect the color of the final soup – the green won’t be as bright and the flavor will be less delicately grassy. But the flavor will be more robust and nutty.
I don’t mean to tell you not to brown your fennel at all, but just let you know about this tradeoff. If you want a really refreshing and green soup, keep the heat to medium-low or lower and take care not to get any brown spots on the fennel or onion. Otherwise feel free to blister them a bit.
Tweak the Consistency If Needed
You may find the soup a bit thicker once it has chilled. You can add a bit of water or vegetable stock to thin it out if you need. Taste it once you’ve thinned it out and add salt to taste.
I wanted a dish that elevated the cooling power and lovely fragrance of fennel and I’m happy with how this came out. Let me know in a comment if you have any questions and I hope you enjoy this.
Chilled Fennel Soup
- 1 Bulb Fennel
- ½ Sweet Vidalia onion sliced thinly
- ¼ teaspoon salt + ⅛ teaspoon, plus more to taste
- 1 liter vegetable stock or broth see note
- 1 Cucumber peeled and cubed (½ inch or 1 cm)
- 2 Tablespoons dill chopped finely
- Lemon zest to taste
- Olive oil for drizzling
Cut the Fennel
- Cut apart the fronds, stalks, and bulb of the fennel. Set the fronds aside in two batches, with about ¼ cup for garnish (these should be the thinnest ones) and put the rest in the bowl of your blender.
- Carefully slice the bulb and stalks as thinly as possible. Discard the outer root-end piece from the stalk.
Saute the Fennel and Onion
- Heat 2 Tablespoons of olive oil in a large skillet over medium-low heat. When hot, add the onion and fennel bulb and stalks, sprinkle with ¼ teaspoon of salt and gently saute, stirring frequently, until tender and translucent all the way through (see note), about 12-14 minutes.
- Blend the Fennel and Onion with Broth
- Add the sauteed fennel and onion and the vegetable stock/broth into the blender with the fennel fronds. Blend on high speed until smooth, 2-3 minutes with a Vitamix blender (see note). Taste the blended soup and stir in salt to taste if needed. Pour the soup into a large bowl or sealable container to cool.
Saute the Cucumber (Briefly)
- Heat the remaining 1 Tablespoon of olive oil in the same skillet over low heat. When hot, add the cucumber cubes and sprinkle with ⅛ teaspoon of salt. Saute, stirring often, until barely translucent on most sides, 2-3 minutes.
- Transfer the cucumber cubes into the container with the soup.
Chill, Then Garnish and Serve
- Cover the soup and if it’s hot, allow it to cool before putting it in the refrigerator. Chill until cold, at least 1 hour.
- Distribute the soup and cucumber cubes into serving bowls. Garnish generously with chopped dill, fennel fronds, lemon zest, and a drizzle of olive oil.
You can caramelize the onion and fennel a bit using higher heat, if you like, though it will affect the color. See blog post above for further info.
The final consistency of the soup will depend in part on your blender. You may need to blend for longer than this to achieve the desired consistency.