Recipe: Wild Watercress, Kelp, and Cauliflower Soup

Recipe: Wild Watercress, Kelp, and Cauliflower Soup

With Crispy Fermented Jerusalem Artichokes

Nutrient-rich seaweed and crispy sunchokes make this soup special.

This is a beautiful, vibrant green spring soup that comes together quickly and is simple to prepare. Wild watercress has a refreshing, clean, and peppery flavor that is balanced out by the deeply savory umami taste of kelp, while cauliflower lends its silky texture to this mineral‑rich springtime soup. Yields four generous servings.

Crispy Fermented Jerusalem Artichokes

Note: prepare the fermented Jerusalem artichokes at least three days in advance.


  • 3–4 Jerusalem artichokes (sunchokes)
  • 2 tbsp pickling spice
  • 6 cloves garlic
  • 1 tbsp Himalayan sea salt
  • Garlic salt to taste
  • Olive oil


It isn’t necessary to ferment the Jerusalem artichokes prior to roasting. It does, however, add a tangy flavor and supports ease of digestion. If you prefer to skip the fermentation process, simply wash the Jerusalem artichokes, then proceed to the roasting steps.

To ferment: Gather enough Jerusalem artichokes to fill a small jar. Wash the tubers, but do not peel. Add 2 tablespoons of pickling spice and 6 garlic cloves to a medium jar. Add tubers, leaving an inch of space at the top.

Dissolve Himalayan sea salt in 4 cups of filtered water, then pour into the jar, ensuring the tubers are covered. Close jar and leave at room temperature until fermentation begins, about 3 to 4 days. When the contents are actively bubbling, store the jar in the fridge until ready to use. (The fermented Jerusalem artichokes will keep for up to one month.)

To Roast: While the soup cooks, slice raw or fermented Jerusalem artichokes thinly with a mandoline. Use a paper towel to pat the slices dry. Toss slices with garlic salt and a drizzle of olive oil until coated. Roast on the prepared baking sheet until the edges are starting to brown and chips are crispy (about 20 minutes), tossing occasionally to ensure even roasting.

Wild Watercress, Kelp, and Cauliflower Soup


  • 1 medium onion
  • 2 medium carrots, peeled
  • 2 stalks celery
  • 1 leek
  • 3 tbsp unsalted butter
  • 1 cup cauliflower florets
  • 3–5 strips dried bull kelp
  • 3 bunches fresh wild watercress, roughly chopped
  • Sour cream or coconut milk (optional)
  • Salt (optional)


Preheat oven to 425F and line a baking sheet with parchment.

Peel and roughly chop onion, carrots, celery and leek. In a large saucepan, melt butter and add onion, carrots, celery, leek, cauliflower and kelp strips. Stir and cook until onion is translucent, 5 to 6 minutes. Add enough water to cover vegetables and bring to a boil, then reduce to a simmer and cover. Simmer until vegetables have softened, about 15 to 20 minutes.

Finish Soup and Serve

Remove soup from heat; add watercress and cover. Allow the greens to gently wilt, about 2 to 3 minutes. Use an immersion blender to purée soup to a smooth consistency.

Ladle puréed soup into bowls. Stir in a spoonful of sour cream or coconut milk, if using. Add salt to taste if needed (bull kelp often provides enough salt so additional salt may not be necessary). Garnish with Crispy Fermented Jerusalem Artichokes.

Reprinted from The Science and Spirit of Seaweed: Discovering Food, Medicine and Purpose in the Kelp Forests of the Pacific Northwest (Harbour Publishing) by Amanda Swinimer courtesy of Harbour Publishing.

Seaweed Recipe Excerpt Image2

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