Buttermilk Summer Squash Soup Recipe

A pureed summer squash soup with a buttermilk twist. I used a hint of red pepper, a bit of rosemary for depth, some potato for body, garlic, shallots - and aside from the buttermilk, nothing too far beyond the usual suspects.

Buttermilk Summer Squash Soup

This is a simple soup I made the other night with the summer squash left over from the gratin we talked about last week. Nothing fancy, just a pureed summer squash soup with a buttermilk twist. I used a hint of red pepper because, quite honestly, I often prefer it over black pepper. I used a bit of rosemary for depth, some potato for body, garlic, shallots - and aside from the buttermilk, nothing too far beyond the usual suspects. And I have to say, while I heartily enjoyed the soup as a main component of our dinner, I enjoyed the leftovers even more the following day.

Buttermilk Summer Squash Soup Recipe

There was plenty of soup leftover, so when Wayne and I decided to throw our cameras in the car and head toward Pt. Reyes for an impromptu photo excursion, I decided to pack a picnic lunch for us. The leftover soup was poured into a large Mason jar, and it ended up being the ideal companion for a day-old chunk of walnut bread that we brought along as well. We found ourselves a shady picnic table in the heart of the little town of Tomales, and the nice ladies at the Tomales Bakery donated a couple of spoons to our cause.

I have to say, it was a near perfect California lunch - wildflowers in bloom everywhere, clear skies, good food, breezes coming off the ocean a few miles west, a vintage cornflower blue Karmann Ghia parked in the grass on the corner, neighbors chatting as they picked up their mail from the post office. And I think it must be little moments like these that keep me from straying too far from the place I've called home (nearly) my entire life.

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Buttermilk Summer Squash Soup Recipe

I happened to have a bit of buttermilk to use up here, and I like the creamy tang it brings to the soup, but feel free to add a splash of creme, or half & half, or a swirl of creme fraiche instead if that's what you have. If you like a deeper green soup (and some bonus nutrition), add a handful of chopped spinach toward the very end - a minute or so before pureeing.

a generous splash of olive oil or (3T.) knob of butter
3 large shallots, chopped
a couple pinches of fine-grain sea salt
pinch of crushed red pepper flakes
3-inch sprig of rosemary
1 1/2 pounds yellow or green summer squash, cut into 1/2-inch thick slices/chunks
3/4 pound potatoes, un-peeled, cut into 1/4-inch thick pieces
3 medium cloves garlic, chopped
3 cups lightly flavored vegetable stock or water
2/3 cup buttermilk

garnish with: fresh herbs, toasted almonds, a generous drizzle of olive oil/ melted butter, and/or some crumbled feta

Heat olive oil/butter in large thick-bottomed pan over medium heat. Stir in the shallots, salt, red pepper flakes, and rosemary. Saute until shallots are tender - a couple minutes. Stir in the squash and potatoes, and cook until the squash starts to get a bit tender - a few minutes. Stir in the garlic, remove the sprig of rosemary, and then add the stock (or water) to the pot. Bring to a boil and then reduce the heat to a simmer, stirring occasionally until potatoes are tender, about 15 minutes.

Puree with a hand blender. If you like a silkier soup feel free to pour the soup through a strainer. Slowly whisk in the buttermilk, taste, and adjust the seasoning - adding more salt if needed. I like this soup topped with a bit of crumbled feta, some toasted almonds, a drizzle of olive oil, and a small pinch of red pepper - but it's perfectly good straight with no fuss on top.

Serves 6 - 8.

If you make this recipe, I'd love to see it - tag it #101cookbooks on Instagram!

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This soup is simply delicious. I added some leaks as I had some in my fridge. This recipe is a keeper! Nina


I just read the recipe this morning and made the soup this evening. It was wonderful! Thank you so much fro all your amazing recipes. I look forward to cooking even more of your delicious dishes!


Lovely! I adore the idea of a feta crumble on top ~ brilliant idea. Heidi, the description of your picnic in Tomales makes me miss home very much. Lots of happy memories in the Pt Reyes area. :)

Mari at Once Upon a Plate

This looks so summery. I can't wait to make it!

Nutmeg Nanny

I've strayed quite far from the place I call home, which is where you are at now. The San Francisco Bay Area is such a special place - I miss it desperately every single day. My garden (squash included) is starting to flower in the south bay and I'm missing it.


Great idea! Thanks for all your helpful little tips, like throwing spinach in to make it greener, and substitutes for the buttermilk!


Now I know what I'll be making when the zucchini is exploding out of my fridge! Looks fantastic!

Cookin' Canuck

This is great! I was just planning to make the Summer Squash Gratin tonight for dinner. What a wonderful idea for the leftover squash (if I have any...)!

Amy Warden

Delicious idea! I love summer soups...


Haven't made this yet but the photo is simply stunning, Heidi. Simplicity is gorgeous. Love your work :)


It looks delicious! My problem, as always, is a lack of food processor. Did this soup look appetizing/edible pre-puree? I know I have to invest sometime, but in the meantime, I wonder if this soup and others can be served without the creamy texture. Thanks, Samantha HS: Hi Samantha, you know, the soup looked o.k. pre-puree. I use my hand-blender all the time, and it was relatively inexpensive. Really easy to clean as well.


If we were to make it from the gratin, what would we do for that? Would you just add as you like, or would you add a certain amount of the leftovers? Your blog is so wonderful!! I love reading the new recipes, and I gives me new insight on healthful cooking. Thank you! Lauren :)


the soup looks lovely, we make something like this in India with split chickpea n without cheese which is not a traditional ingredient here. your picnic story in enticing.pictures are great as always.......i like the rustic charm in your pics.

sangeeta khanna

The entire thing sounds absolutely spectacular! A very lovely picnic, indeed.You're making me miss California. P.S do you think one could omit the buttermilk and use a bit more potatoe for lactose intolerance?


The south abounds with squash and this option will come in handy. This week I am on a squash kick, if you will, and this might have to debut real soon.


The crumbled feta on top is just the touch of taste and contrast in color. Delicious.

The Duo Dishes

This looks lovely! I'm wondering what you think would happen if I replaced the potatoes (some? all?) with white beans. It would serve a similar thickening purpose, while getting beans into my daughter!


I am eating your delicious black bean salad for lunch, dreaming about the squash gratin, and planning for the soup while I soak up every detail you've written about Point Reyes. I grew up in Marin and am now in Ohio plotting a way to return and am momentarily sustained by your entry today. Thank you. I am so glad I found your site.


For the vegan alternative, you could use soy milk with a little apple cider vinegar stirred in. Or the coconut milk and add a little vinegar. That would give you the "tang" like buttermilk.


I often make a similar soup and in fact do use coconut milk instead of buttermilk. Sometimes I use both.


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