Sweet Potato Pear Soup

Ingredients:

1  Cup chopped onion

½  Cup sliced celery

2  Teaspoon vegetable oil

3  Cups pared, cubed sweet potatoes

2  Cups pared, cubed Anjou or Bosc pears

4  Cups reduced-sodium, defatted chicken broth

½  Cup vermouth

1  Cinnamon stick

1/2  Teaspoon dried thyme leaves

1/4  Teaspoon ground nutmeg

¼  to ½  Teaspoon salt

¼  Teaspoon pepper

1  Cup low-fat yogurt

1  Anjou or Bosc pear, cored

Instructions: