I had a bite of this zucchini soup and the first word I said was “WOW.” It’s supremely flavorful, and one of my favorite ways to use zucchini as we transition from late summer to fall. Zucchini is a great addition to soups, and this recipe uses it in both a grated form and as big chunks. The chunks of zucchini simmer along with potatoes, and they both melt into a similar texture — rich, hearty, and packed with flavor in every bite.
The consistency of the soup is built through a velouté-style stock. While this sounds fancy, this just means that we build and thicken the broth by starting with a light roux, and then adding vegetable stock. It’s a traditional French mother sauce, but I opt for vegetable stock instead of chicken stock, just to keep it vegetarian. The entire soup is a one-pot-wonder, and I hope it will make your fall rotation this season!
Table of contents
Ingredients you will need for this zucchini soup
This zucchini soup builds on flavors, here is everything you will need to make it:
- 3 large zucchini, 30 ounces / 850 grams
- 3 cups small Yukon Gold potatoes, 24 ounces / 680 grams
- 1 large yellow onion, 12 ounces / 340 grams
- 4 garlic cloves
- 1/4 cup extra-virgin olive oil
- 1 lemon for zest and juice
- 1 teaspoon freshly ground black pepper, plus more to taste
- 2 teaspoons Diamond Crystal kosher salt, plus more to taste
- 1 teaspoon caraway seeds
- 1 teaspoon red pepper flakes
- 4 tablespoons salted butter, 2 ounces / 57 grams
- 1/3 cup all-purpose flour, 1.6 ounces / 46 grams
- 4 cups unsalted vegetable stock, 32 ounces / 907 grams
- 2 cups water, 16 ounces / 453 grams
- 1 cup fresh parsley, 1.5 ounces / 42 grams
How does this soup get its texture?
This soup has a creamy consistency similar to chowder, and that’s coming from a combination of the zucchini, potatoes, and the velouté soup stock.
The zucchini is both grated and chopped, so the grated zucchini adds moisture and a thicker texture to the soup. As the soup simmers, the potatoes that we add release their starches, which adds a natural thickness.
And then there is the building of the stock of the soup, which starts with a roux. A “roux” is just fat plus flour, and it’s often used in French cooking, Cajun cooking, and Soul Food alike. When you cook down a roux, you are toasting the rawness out of the flour. From there, you gradually add milk, broth or stock until a thickened sauce starts to form. This recipe uses stock to start the sauce, and it helps the soup start with a rich, flavorful broth that only gets creamier as we add ingredients. A roux is one of my favorite ways to start a soup, and it’s part of the reason this soup is so good.
What is lemon pepper polenta?
Toasted lemon pepper polenta is a mad-science creation of my own invention (I think? I’m sure it’s been done before). But with my soups I always need a little *something* crispy on top, whether that’s croutons, crispy rice nuggets, or just toasty bread on the side. With this soup, I wanted something a little lemony, but also rich with corn-fried flavor. Enter scene: polenta. My perfect answer.
While the soup is simmering, it takes only minutes to add the polenta to a pan with lemon juice, salt, pepper and olive oil, and toast it down into crunchy, nutty, roasty goodness. From there you just scatter it on top of the soup, and it is texture HEAVEN.
Looking for other soup recipes?
Here are a few favorites from the blog!
And that’s it for this Zucchini Soup with Lemon Pepper Polenta!
If you make it, please tag me on Pinterest or Instagram so I can see! It’s my favorite thing to scroll through stories and see what you all are making.
And of course feel free to leave any questions, comments or reviews! This is the best place to reach me, and I’d love to hear from you <3
Watch the recipe here
The video may not fully represent the recipe. For best results, follow the instructions as written.
Zucchini Soup with Lemon Pepper Polenta
Equipment
- 1 chef's knife
- 1 rasp-style grater
- 1 7-quart Dutch oven or large pot
Ingredients
- 3 large zucchini 30 ounces / 850 grams
- 3 cups small Yukon Gold potatoes 24 ounces / 680 grams
- 1 large yellow onion 12 ounces / 340 grams
- 4 garlic cloves
- 1/4 cup extra-virgin olive oil
- 1 lemon for zest and juice
- 1 teaspoon freshly ground black pepper plus more to taste
- 2 teaspoons Diamond Crystal kosher salt plus more to taste
- 1 teaspoon caraway seeds
- 1 teaspoon red pepper flakes
- 4 tablespoons salted butter 2 ounces / 57 grams
- 1/3 cup all-purpose flour 1.6 ounces / 46 grams
- 4 cups unsalted vegetable stock 32 ounces / 907 grams
- 2 cups water 16 ounces / 453 grams
- 1 cup fresh parsley 1.5 ounces / 42 grams
For the lemon pepper polenta
- 1 cup polenta 5 ounces / 145 grams
- 1 teaspoon Diamond Crystal kosher salt
- 1 teaspoon freshly ground black pepper
- 3 tablespoons extra-virgin olive oil
Instructions
- Begin with the mise en place. Quarter one zucchini lengthwise, then slice it crosswise into bite-sized pieces. Use a rasp-style grated to grate the remaining two zucchini. Add this all to a large bowl and set aside.
- Quarter the potatoes. Add them to the zucchini bowl.
- Finely dice the onion and grate the garlic. Set these to the side.
- Place a 7-quart Dutch oven (or large pot) over medium heat. Add 1/4 cup of olive oil and let it heat up for a few minutes.
- Add in the onion and cook for 5-6 minutes, stirring often. While the onion is cooking, grate in two teaspoons of lemon zest (nearly the whole lemon). Crack in 1 teaspoon of freshly ground black pepper and season with 1 teaspoon of salt. Add 1 teaspoon of caraway seeds and 1 teaspoon of red pepper flakes. Stir to combine.
- Add the garlic and cook an additional 4-5 minutes, or until the onion is taking on a touch of color and the garlic is fragrant.
- When the onion has softened, add in the 4 tablespoons of butter. Let this melt fully and reduce the heat on the pot to low. Add 1/3 cup of flour and mix everything into a paste.
- Pour in the vegetable stock about 1/3 cup at a time, being sure to mix it into the pot well before adding another 1/3 cup. It will start to form a thick and creamy soup base. Season with another teaspoon of salt.
- When all of the broth has been added, add the zucchini and potatoes to the pot. Stir and add 2 cups of water. Bring this to a simmer, cover and let simmer for 45 minutes. This will build flavor and get both the zucchini and potatoes to an amazing texture.
- While the soup is simmering, finely chop the parsley and set it aside. Halve the lemon and set that aside, too.
- To make the polenta topping, set a large pan over medium heat. Add the 1 cup of polenta and season with 1 teaspoon of salt and 1 teaspoon of pepper. Squeeze in the juice from half the lemon and drizzle in 3 tablespoons of olive oil. Stir often and toast until the polenta starts to turn golden brown, about 5-6 minutes. Taste and season with salt as preferred. Set aside.
- When the soup is done simmering, stir in the chopped parsley and squeeze in the juice from the remaining lemon half. Taste and season with salt as preferred.
- To serve, ladle into six bowls, top each with the lemon pepper polenta and enjoy!
Craving a bit of protein to serve the soup as a meal, I added raw cashew pieces at end. Thought about adding butter beans but didn’t want to them to compete with the potatoes. Gave it a tad more chew and texture.
I recommend roasting in the oven or airfryer the cashews, whitebeans, or chickpeas until crunchy,and topping on the soup. Make sure they are dry before going in the oven. To get that lemony flavor, marinate them with olive oil, lemon, and a little salt. My kids snack on these and love them.
A marvel of a recipe ! I appreciate the combination of techniques beginning with the roux to finish off with the crispy crumble dust. I have only been missing the lemon part in the polenta ingredients list and details on what kind of polenta we’re talking. I believe it’s being still dry right ? If so at what point do you add the lemon juice ? Thank you
Hi Jill! Yes, the polenta is still dry. And apologies for any confusion on the lemon amount! There is a full lemon listed in the soup ingredients, and you’re using the remaining lemon half to squeeze into the polenta. It should specify that in the instructions, but we only list the lemon once so someone isn’t buying two lemons for no reason!
Loved it! Great as an end of winter kind of soup. The polenta topping was a great hit as well-
This was the perfect soup to use up what little I have in the fridge and pantry! I didn’t have caraway seeds, so I substituted with some dried fennel seeds. The recipe is perfect on its own, but I added some leftover Mayacoba beans that I cooked in various herbs to my bowl too, it really helped the soup feel so much more filling. It’s delicious even without the beans. The lemon pepper polenta was such a perfect addition to the soup. Will definitely be making this again!
If anyone else would have suggested boiling zucchini for that long, I would have been skeptical. But if Justine says it, I trust her blindly! and I was not disappointed. As my partner repeats with each of your recipes that I prepare (and I have made ALOT of them): Justine knows what she’s doing!