Spiced Rhubarb Soup

Directions

1. In a large saucepan, bring rhubarb, 3-1/4 cups water, sugar, cinnamon sticks and salt to a boil. Reduce heat; simmer, uncovered, for 20 minutes or until rhubarb is tender. Discard cinnamon sticks. Strain rhubarb mixture; discard pulp. Return liquid to the pan; bring to a boil.
2. Combine cornstarch and remaining water until smooth; stir into saucepan. Cook and stir for 2 minutes or until thickened. Remove from the heat; add lemon slice. Cover and refrigerate until chilled. Discard lemon slice. Ladle soup into bowls. Garnish each serving with 1 tablespoon sour cream.