• 1 tablespoon olive oil
• 1 medium onion , chopped
• 1 rib celery , chopped
• 1 clove garlic , chopped
• 2 pounds carrots , scrubbed but unpeeled, cut into 1/2-inch thick rounds
• 1 tablespoon Madras-style curry powder
• 1 teaspoon ground ginger
• 5 cups reduced-sodium chicken broth
• 1 cup plain nonfat yogurt or light coconut milk , optional
• Salt and freshly ground pepper , to taste

Heat the oil in a large saucepan over medium heat. Add the onion, celery, and garlic and cover. Cook, stirring occasionally, until the onion is golden, about 5 minutes. Add the carrots and stir well. Stir in the curry powder and ginger and cook, stirring almost constantly, for 30 seconds.

Add the broth and bring to a boil over high heat. Reduce the heat to medium-low and partially cover the pot. Simmer until the carrots are very tender, about 30 minutes.

In batches, transfer the soup to a blender, process until smooth and pour the puréed soup into a large bowl. (If you have an immersible hand blender, you can purée the soup right in the pot.) Return the puréed soup to the pot. If desired, stir in the yogurt or coconut milk and stir over low heat just until the soup is very hot; do not simmer. Season the soup with salt and pepper. Serve hot.