Roasted Cauliflower Mushroom Garlic Walnut Soup (Meatless Monday)

Roasted Cauliflower Soup recipe, roasted mushroom soup, roasted garlic soup, roasted walnut soup, vermouth, cream, stock,

Roasted Cauliflower Soup

Oven-Roasted Cauliflower, along with Mushrooms, Garlic and Walnuts combine with sautéed onions, celery and carrot; herbs, vegetable stock, vermouth and cream for an incredibly flavorful as well as hearty soup that’s perfect for cold weather and for Meatless Monday.  

I really love the nutty flavor of roasted cauliflower, so when I decided to make a cauliflower soup, it was a natural to oven roast it before adding it to the soup. Then, I looked in the refrigerator and pantry for a little inspiration and decided to add mushrooms for a meaty texture, garlic for a sweet roasted garlic flavor, and walnuts for a punch of nuttiness as well as nut protein.

For the liquids, of course, I had to use vermouth. I’ve often talked about why I use vermouth so much in cooking, but it bears repeating. Dry White Vermouth is superior to using just a dry white wine (although you could use one instead) because vermouth is an aromatized, fortified wine that is infused with botanicals (roots, barks, flowers, seeds, herbs and spices). Because of that, it adds a lot of dimension of flavor.

Since I was making this soup for Meatless Monday, I used a vegetable stock. You could use the stock of your choice. Any would work beautifully.  Additionally, I used a bit of cream for a thick, rich consistency.

Once the cauliflower, mushrooms, garlic and walnuts were roasted, I sautéed some onion, celery and carrot in a bit of butter. The soup is further seasoned with some fresh parsley, dry marjoram and rosemary.

While I left this soup chunky, you could use either a blender or an immersion blender to make a creamed soup. Either way, it’s rich and thick; it’s hearty; it’s loaded with flavor.

I hope you’ll try it!


5.0 from 1 reviews
Roasted Cauliflower Mushroom Garlic Walnut Soup (Meatless Monday)
Prep time
Cook time
Total time
Serves: 8 cups
  • 8 cups of cauliflower florets (about 2 medium heads)
  • 8 ounces sliced mushrooms
  • 1 cup walnuts pieces
  • 2 heads garlic
  • 2 tablespoons olive oil (I used a garlic infused)
  • 2 teaspoons olive oil (plain)
  • 2 tablespoons unsalted butter
  • 1½ cups diced onion (about 1 large onion)
  • 1 cup diced carrot (about 2 carrots)
  • 1 cup diced celery (about 2 ribs)
  • 1 cup extra-dry white vermouth
  • ¼ cup all-purpose flour
  • 1 (32-ounce) containers vegetable stock
  • 1 cup water
  • 2 tablespoons chopped fresh parsley
  • 2 teaspoons dry marjoram leaves
  • ¼ teaspoon crushed dry rosemary
  • 1 cup heavy whipping cream
  • 1½ teaspoons kosher salt
  • 1 teaspoon ground black pepper
  1. Preheat oven to 400°.
  2. Spread cauliflower, mushrooms and walnuts on prepared baking sheet, and drizzle with 2 tablespoons olive oil.
  3. Toss to coat.
  4. Trim about ¼ inch from top of garlic heads, exposing tops of garlic cloves.
  5. Pour 1 teaspoon oil over each garlic clove, and wrap with aluminum foil to cover.
  6. Place on baking pan with cauliflower, mushrooms and walnuts.
  7. Roast in oven for 40 minutes, stirring cauliflower halfway through, or until florets are tender when pierced and edges are starting to brown.
  8. Remove cauliflower from pan, and set aside.
  9. Return garlic to oven, and roast 10 to 15 minutes more.
  10. Let garlic heads cool for 15 minutes.
  11. Gently unwrap garlic heads. Squeeze each garlic head to remove roasted cloves from their skins.
  12. Mash garlic cloves with a fork and set aside.
  13. In a large Dutch oven, melt butter over medium heat. Add onion, carrot, and celery, cover and cook until tender, 5-8 minutes.
  14. Add vermouth and allow to cook for about 4 minutes.
  15. Add the cauliflower, mushrooms, walnuts and mashed garlic and cook for 4 minutes.
  16. Add flour, and cook for 2 minutes, stirring constantly.
  17. Gradually stir in stock, water, parsley, marjoram, rosemary, cream, salt and pepper.
  18. Bring to a boil over medium-high heat; reduce heat, and simmer for 20 minutes.


About P ~ The Saucy Southerner

I started cooking when I was ten years old. For me, the process of cooking, from inception of a dish, to the execution, to the washing of the pots is sheer delight. I am now retired from a business I still own, in partnership with my husband. I used to work six days a week and still cook every night. Now, I'm gardening, still cooking, always having fun and hoping to share my joy with you. Thank you for reading...and commenting! P~
This entry was posted in Entrée, Living in Elegant Simplicity, Meatless Monday, Saucy Southerner Recipes, Soups, Vegetables. Bookmark the permalink.

2 Responses to Roasted Cauliflower Mushroom Garlic Walnut Soup (Meatless Monday)

  1. laura says:

    This combo is STUNNING I’ve never put walnuts in soup but it’s intriguing!! You know I pinned it : )

    <3 Thanks for linking up to the Friday Frenzy-we appreciate you!

    • Thank you! I put in the walnuts because I really wanted to highlight the nutty cauliflower flavor. They were great in it! Interestingly, because they didn’t know they were in there, neither Mr. Saucy nor some friends I shared it with even realized they were there. P~

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