2 teaspoons vegetable oil
1 large onion, chopped (about 1 cup)
1 medium rib celery, sliced (about 1/2 cup)
3 medium sweet potatoes, peeled and cubed (about 3 cups)
2 ripe medium pears, peeled and cubed (about 2 cups) or plus one small ripe pear for garnish
4 cups low-sodium chicken broth
1/2 cup dry vermouth
1 cinnamon stick
1 teaspoon finely grated orange zest
1/2 teaspoon dried thyme
1/4 teaspoon ground nutmeg
1/4 teaspoon salt
1/4 teaspoon freshly ground black pepper
8 ounces low-fat plain yogurt (optional)
finely chopped fresh parsley for garnish
In a large saucepan, heat the oil over medium heat. Add the onion and celery and cook for about 10 minutes, or until soft but not browned. Add the sweet potatoes, pears, chicken broth, vermouth, cinnamon stick, orange zest and thyme. Bring to a boil; reduce the heat and simmer, covered, for 35 to 45 minutes, or until the sweet potatoes are tender. Remove the cinnamon stick.
In a food processor or blender, purée the vegetable mixture, in batches, until smooth. Return the purée to the saucepan and stir in the nutmeg, salt, and pepper. Cook over medium heat until heated through.
To serve, halve, core, and cut the pear into 6 wedges. Cut each wedge to form a fan. Ladle the soup into bowls and top with a dollop of yogurt, if desired. Garnish each serving wtih a pear fan and sprinkle with parsley.