Roasted Spicy Purple Cauliflower Soup

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Red pepper flakes give this vegan roasted spicy purple cauliflower soup some heat. It is hearty and filling thickened with purple fingerling potatoes.

Roasted Spicy Purple Cauliflower Soup
It can take me a couple days to finalize my grocery list.

Yes, I know that seems like a ridiculous amount of energy.

When I do get to the store, usually all that time doesn’t even matter. Without fail, something I have my heart set on will be out of stock.

And that missing item will be a key ingredient in a recipe.

But my shopping trip can go the opposite way, too.

I will find something that I never planned to buy that day, and it immediately becomes the must-have item I absolutely can’t live without.

Actually, that happened to me on my last trip.

Across the produce department I spied cauliflower in every color—white, orange, green and purple.

Rainbow cauliflower is the first thing that came to my mind, but instead I settled on just purple.

I put two heads into my cart along with purple fingerling potatoes.

My color-coded shopping resulted in this roasted spicy purple cauliflower soup.

Roasted Spicy Purple Cauliflower Soup

How To Make Roasted Spicy Purple Cauliflower Soup

No matter the hue, this simple vegan soup turns out hearty and filling.

First, I toss the cauliflower on a sheet pan with olive oil, salt, pepper and red pepper flakes.

Then I roast it at 375 degrees F until the cauliflower is lightly browned at the edges.

The red pepper flakes are what gives the soup some heat.

Once the cauliflower is roasted, I get to work on the stovetop.

I sauté chopped onions in a saucepan with minced garlic and more red pepper flakes.

After that, I add the cauliflower, diced purple potatoes and water.

I use water instead of veggie stock for aesthetic reasons because I don’t want to take away the purple color from the cauliflower and potatoes.

The soup simmers for just 10 minutes.

Finally, I puree it in the blender.

I top each bowl with some of the roasted cauliflower that I set aside.

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Roasted Spicy Purple Cauliflower Soup

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Prep: 15 minutes
Cook: 45 minutes
Total: 1 hour
Servings: 4
Red pepper flakes give this vegan roasted spicy purple cauliflower soup some heat. It is hearty and filling thickened with purple fingerling potatoes.


  • 1-1/2 pounds purple cauliflower trimmed and broken into florets*
  • 1/2 pound purple fingerling potatoes or purple sweet potatoes diced
  • 2 tablespoons olive oil
  • 1/4 teaspoon crushed red pepper flakes plus more for serving
  • 1-1/2 teaspoon kosher salt
  • 1/2 teaspoon black pepper
  • 1 small red onion roughly chopped*
  • 1 garlic clove crushed
  • 3 cups water
  • Fresh chives for serving


  • Preheat the oven to 375 degrees F. Toss the cauliflower and potatoes with 1 tablespoon olive oil, 1/8 teaspoon red pepper flakes, 1/2 teaspoon salt and 1/4 teaspoon black pepper. Roast the cauliflower until it is tender and the florets are starting to brown at the edges, about 25 to 30 minutes.
  • Heat the remaining olive oil in a large saucepan over medium heat. Add the onions and sauté for 5 minutes until they start to soften. Stir in the garlic and remaining red pepper flakes, salt and pepper and continue cooking for an additional 3 minutes. Add the water cauliflower and potatoes, reserving 1/2 cup cauliflower for garnish. Simmer the soup for 10 minutes.
  • Carefully transfer the soup in batches to a blender to puree. Return the soup to the saucepan to reheat before serving, Divide into bowls and top with cauliflower, fresh chives and red pepper flakes.


*If you have white, orange or green cauliflower, use a white onion instead of red.


Calories: 161kcal | Carbohydrates: 21g | Protein: 5g | Fat: 8g | Saturated Fat: 1g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 5g | Sodium: 937mg | Potassium: 794mg | Fiber: 5g | Sugar: 5g | Vitamin A: 3IU | Vitamin C: 95mg | Calcium: 59mg | Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Additional Info

Course: Soup
Cuisine: American
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Hi, I'm Paige.

Welcome to Last Ingredient where you will find simple seasonal recipes with plenty of fruits and vegetables, all for the home cook.

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