Creamy Roasted-Broccoli Soup With Buttermilk and Spiced Pepitas Recipe

A warming fall soup with the deep flavor of roasted broccoli and a gentle buttermilk tang.

By
Daniel Gritzer
Daniel Gritzer
Editorial Director
Daniel joined the Serious Eats culinary team in 2014 and writes recipes, equipment reviews, articles on cooking techniques. Prior to that he was a food editor at Food & Wine magazine, and the staff writer for Time Out New York's restaurant and bars section.
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Updated October 02, 2024
Overhead closeup of creamy roasted-broccoli soup with buttermilk, served in a bowl and topped with spiced pepitas

Serious Eats / Daniel Gritzer

Why It Works

  • Roasting the broccoli concentrates its flavor and adds deep, savory notes from Maillard browning.
  • Buttermilk adds creaminess and a balanced acidity.
  • Adding olive oil to the soup as it blends provides extra richness.
  • The seasoned pumpkin seeds add textural contrast, yet more roasted notes, and little bursts of spicy, herbal, and lemony flavor.

I shop at the farmers market with the best intentions, but I'll admit that sometimes my enthusiasm is greater than the time I have to cook everything I buy. Just last week I picked up a beautiful bright green head of broccoli with tight florets, then let days pass without doing anything with it. Eventually I opened the fridge and saw it languishing there, a slight sag to its stalks, the vivid green washing away.

It hadn't gone bad, but it wasn't at its best. Situations like that call for soup: blended, creamy soup. Because my broccoli had lost its zest, I didn't want to try to capture its freshness by blanching it. Instead, I opted for the more significant transformation of roasting—it was already headed to dried and brown on its own, why not take it there a lot faster and get some good flavor out of it at the same time?

Now, that was the reality behind my version of this soup, and it's a good lesson in resourcefulness.* But of course I advise you to use fresh broccoli that's still at its peak. My soup tasted very good with not very good broccoli, yours will taste even better with good broccoli.

*A better lesson, though, would be me learning to cook the broccoli sooner, or buying less at the farmers market each week.

Closeup of roasted broccoli on a sheet pan.

Serious Eats / Daniel Gritzer

To make the soup, I followed a tried-and-true creamy-soup-making method, which Kenji has detailed excellently in this piece. I started by tossing my broccoli in olive oil and roasting it until browned and tender.

Then I sweated onion and garlic in olive oil, flavored it with some coriander seed and crushed red pepper, and added the broccoli.

The roasted broccoli is added to the pot with the onions and garlic.

Serious Eats / Daniel Gritzer

I added some buttermilk, for a light dairy flavor and tang, along with vegetable stock, and blended it all until smooth, working a little extra olive oil into the puree in the blender. It'll come out of the blender a little thick, but you can return it to the pot and thin it with more vegetable stock until the consistency is just right.

As Kenji describes in his creamy soup article, it's nice to add a little touch of acid to a finished soup, but in this case I left it out since the buttermilk is already lending it just enough tartness.

Overhead view of spiced, toasted pepitas on a sheet pan.

Serious Eats / Daniel Gritzer

I had some extra pepitas lying around from my Mexican butternut squash soup, so I tossed them with olive oil and spices like turmeric, cumin, coriander, and mustard seed and toasted them in the oven while the soup was cooking. Once they were done, I mixed in a little extra olive oil along with parsley and lemon zest. It's a great garnish for this soup.

Overh4ead view of the roasted broccoli soup, served in a white bowl on a wooden surface.

Serious Eats / Daniel Gritzer

Eating the soup, no one would have guessed it was a salvage job. Except now I've gone and told the whole world. Dammit.

October 2014

Recipe Details

Creamy Roasted-Broccoli Soup With Buttermilk and Spiced Pepitas Recipe

Prep 5 mins
Cook 50 mins
Active 30 mins
Total 55 mins
Serves 5 to 7 servings
Makes 10 cups
Cook Mode (Keep screen awake)

Ingredients

  • 2 pounds broccoli, stalk trimmed and heads cut into florets

  • 10 tablespoons extra-virgin olive oil, divided

  • 1 large yellow onion, thinly sliced (about 1 1/2 cups)

  • 4 medium cloves garlic, crushed (about 4 teaspoons)

  • 1 teaspoon ground coriander seed, divided

  • 1/4 teaspoon red pepper flakes

  • 1 1/2 cups buttermilk

  • 1 1/2 quarts homemade or store-bought low-sodium chicken stock or vegetable stock

  • Kosher salt

  • 1 cup pumpkin seeds

  • 1/2 teaspoon ground cumin (see note)

  • 1/4 teaspoon ground mustard seed

  • 1/4 teaspoon turmeric

  • 2 tablespoons minced fresh parsley

  • Zest of 1 lemon

Directions

  1. Preheat oven to 375°F (190°C). Toss broccoli with 2 tablespoons olive oil and spread in an even layer on 2 rimmed baking sheets. Transfer to oven and roast until broccoli is tender and browned, about 25 minutes.

    Closeup of roasted broccoli on a sheet pan.

    Serious Eats / Daniel Gritzer

  2. In a Dutch oven, heat 2 tablespoons olive oil over medium-high heat until shimmering. Add onion and garlic and cook, stirring, until softened, about 3 minutes. Stir in 1/2 teaspoon coriander seed and red pepper flakes and cook until fragrant, about 1 minute.

    Onions and garlic are cooked in a Dutch oven.

    Serious Eats / Daniel Gritzer

  3. Add roasted broccoli, buttermilk, and just enough stock to barely cover vegetables. Bring to a simmer, then remove from heat. Working in batches if necessary, transfer vegetables and liquid to a blender. Starting on the lowest speed and gradually increasing to the highest speed, blend broccoli until a smooth puree forms. Drizzle in 4 tablespoons total olive oil while blender is running and return to a clean pot. Add as much of the remaining vegetable stock as necessary to thin to a creamy soup consistency. Season with salt.

    The roasted broccoli is added to the pot with the onions and garlic.

    Serious Eats / Daniel Gritzer

  4. Meanwhile, lower oven to 350°F (175°C). In a mixing bowl, toss pepitas with 2 tablespoons olive oil, remaining 1/2 teaspoon ground coriander, cumin, mustard seed, and turmeric. Season with salt. Transfer to a parchment-lined baking sheet and roast until fragrant, about 10 minutes. Let cool.

    Pepitas are tossed with oil and spices.

    Serious Eats / Daniel Gritzer

  5. Scrape toasted spiced pepitas into a mixing bowl and stir in parsley, lemon zest, and remaining 2 tablespoons olive oil.

  6. Warm the soup, then spoon it into bowls. Top with spiced pepitas and some of their oil. Serve right away.

Special Equipment

Dutch oven, blender, 2 rimmed baking sheets

Notes

As a shortcut, you can substitute the spices used for the pepitas with an equal amount of store-bought curry powder. If the store-bought curry powder is salted, be sure to taste pepitas before adding salt.

Read More

Nutrition Facts (per serving)
316Calories
22gFat
23gCarbs
10gProtein
×
Nutrition Facts
Servings: 5 to 7
Amount per serving
Calories316
% Daily Value*
Total Fat 22g29%
Saturated Fat 3g17%
Cholesterol 2mg1%
Sodium 813mg35%
Total Carbohydrate 23g8%
Dietary Fiber 7g25%
Total Sugars 7g
Protein 10g
Vitamin C 91mg456%
Calcium 153mg12%
Iron 2mg13%
Potassium 812mg17%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

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