Heat the oil in a soup pot over high heat. When the oil is hot, add the onion, potatoes, Jerusalem artichokes and celery. Sauté over high heat, stirring frequently, until lightly browned, about 10 minutes. Add the garlic during the last few minutes. Pour in the water or stock, add 1½ teaspoons salt and the bay leaves and bring to a boil. Lower the heat to a simmer, cover and cook until the potatoes are tender, about 25 minutes.
Let cool briefly, and then remove the bay leaves and purée the soup until smooth. Return the soup to the pot and reheat over gentle heat. Add milk as needed to thin the bisque to the desired consistency. Taste for salt and season with pepper.
Ladle into bowls and drizzle a few drops of the pumpkin seed oil over the surface of each serving. Top each bowl with a few croutons, then finish with a small clump of sunflower sprouts and serve.
With Sautéed Radicchio: Sliver then sauté radicchio in olive oil or safflower seed oil until wilted and browned, then garnish each bowl of soup with it, along with the sunflower sprouts, or not.
Recipe from Deborah Madison, Vegetable Literacy