Cream of Celery Soup (Vellutata di Sedano)
"Make this comforting soup in autumn, when you can find fresh celery at the farmers' market. It makes a big difference. Use some of the leafy tops in the soup and use the rest to flavor broths, sauces and stews, and to put in winter salads. I added a dollop of mascarpone cheese to enrich this soup, but you can use heavy cream or even whole milk. For a lighter version, just leave out the dairy."
2 tablespoons extra-virgin olive oil
1 small onion, diced
1 medium carrot, cut into rounds
1 small russet potato, diced
1 bunch celery, chopped, including some of the tops and leaves
1 teaspoon fine sea salt
Freshly ground black pepper
About 2 cups vegetable or chicken broth, more if necessary
1/4 cup mascarpone cheese or heavy cream
1 tablespoon minced fresh flat-leaf parsley, plus a few leaves for garnish
Celery leaves for garnish
Croutons for serving
In a Dutch oven or heavy-bottomed pot, melt the butter in the oil over medium heat. Lower the heat to medium-low and stir in the onion, carrot, and potato. Cook for about 15 minutes, until the onion is translucent and the carrot is bright orange. Add the celery to the pot, along with 1/2 cup water. Season with salt and pepper. Cover and cook without browning (reduce heat to low if necessary) until all the vegetables are tender, 40 to 50 minutes. Pour in 1 cup of broth, cover, and continue to cook for another 10 minutes. All the vegetables must be soft. Poke a few of the larger pieces with a fork to make sure. Remove from the heat. Use an immersion blender or a standard blender to puree the vegetables, adding more broth as necessary. Return the pot to the heat and stir in the mascarpone or cream. Bring to a simmer over medium-low heat and add more broth if you like to thin out the soup. Taste and adjust the seasoning with salt or pepper. Sprinkle in the parsley and remove from the heat. To serve, ladle the soup into bowls and garnish with parsley and celery leaves. Top with croutons.