Ingredients

1 1/2 tablespoons butter or margarine
1 medium onion, finely chopped
2 teaspoons all-purpose flour
1/3 teaspoon salt
1/4 teaspoon dried tarragon
1 pinch ground nutmeg
1 pinch cayenne pepper
1 (16 ounce) package frozen chopped spinach, thawed
2 cups chicken broth
3/4 cup plain yogurt
2 slices lemon, cut in half for garnish

Directions

Melt butter in a large saucepan over medium heat. Add the onion, and cook until tender, stirring occasionally. Stir in the flour, salt, tarragon, nutmeg and cayenne, and heat until fragrant. Stir in spinach (undrained) and chicken broth. Bring to a boil, then reduce heat to low, and simmer for about 15 minutes.

Remove the soup from the heat, and puree in a food processor or blender in batches. Return to the saucepan, and whisk in yogurt. Heat through, but do not boil. Taste and adjust seasonings if necessary. Ladle into bowls, and float a lemon slice on top of each serving.