Roasting vegetables until they caramelize intensifies their flavor and adds an additional layer of rich flavor to this Roasted Cauliflower Leek and Potato Soup.
Preheat the oven to 425°F (220°C). Line a large rimmed baking sheet with parchment paper.
In a large bowl, toss the 1 large russet potato, ½ a large head of cauliflower , 4 large leeks, 3 stalks of celery, and 4 cloves of garlic with ¼ cup olive oil. Season with salt and pepper to taste.
Arrange the vegetables on the baking sheet in a single layer. Roast the vegetables until the have caramelized and are golden brown. This should take approximately 25 to 35 minutes. Toss the vegetables halfway through the bake time to ensure even browning.
Reserve ¼ of the vegetables for topping the finished soup. Transfer the remaining vegetables to a large pot and add the ½ cup dry white wine. Simmer for 2-3 minutes over medium-low heat.
Add the 6 cups chicken stock and 1 teaspoon dried sage and simmer for an additional 10 minutes.
Add the 2 tablespoons unsalted butter and blend the soup with an immersion blender or transfer to a blender and puree in small batches.
If the soup is too thick add additional chicken stock until you reach your desired consistency. Taste and adjust the seasoning, if necessary.
Serve immediately garnished with reserved vegetables, fresh herbs, and grated Parmesan cheese.
Notes
Cut the vegetables into uniform sizes to ensure even roasting.Don't crowd the roasting pan. Make sure there is enough room for air to circulate around the vegetables. Otherwise, the vegetables will steam rather than roast.To make this soup vegetarian, replace the chicken stock with vegetable stock.If you don’t have an immersion/stick blender you can also puree the soup in a blender. If you’re using a blender, purée the soup in batches. Don’t fill the blender past the maximum fill line, the volume of the soup will expand as you blend. Open the vent to allow the steam to escape.Soup Consistency: If you prefer a thicker soup reduce the amount of chicken stock. If you prefer a thinner soup increase the amount of chicken stock.Storage: If you have leftover soup, allow the soup to come to room temperature and then store it in an airtight container in the refrigerator for 3-4 days.
To Freeze: Allow the soup to come to room temperature and then transfer it to an airtight container or zip-top bag. Label the container with the contents and date. Then freeze the soup for up to three months.