01 - Preheat the oven to 400°F. Toss the salsify pieces with 1 tablespoon olive oil, salt, and pepper. Spread on a baking sheet and roast for 25–30 minutes, turning halfway, until golden and tender.
02 - Meanwhile, in a large pot, heat the remaining 2 tablespoons olive oil over medium heat. Add onion, leek, carrot, and garlic. Sauté for 6–8 minutes, until softened.
03 - Add the roasted salsify, white beans, thyme, and bay leaf to the pot. Stir well to combine.
04 - Pour in the vegetable stock. Bring to a boil, then reduce heat and simmer for 15 minutes.
05 - Remove the bay leaf. Using an immersion blender, blend the soup until smooth and creamy. Stir in the cream, warm through, and adjust seasoning with salt and pepper.
06 - Ladle into bowls. Garnish with chopped parsley and pumpkin seeds, if using. Serve hot.