In a medium saucepan, combine the celery, onion, water, bay leaf, sugar, salt, and pepper. Bring to boiling; reduce heat. Cover and simmer for 10 to 15 minutes or until celery and onion are very tender. Discard bay leaf. Add undrained tomatoes and tomato paste.
Place the vegetable mixture in a blender container or food processor bowl. Cover and blend or process until the mixture is smooth. Strain the mixture through a sieve; set aside. (You should have about 1-3/4 cups).
Add the evaporated fat-free milk to the saucepan. Gradually stir in the blended tomato mixture. Add the butter-flavored sprinkles. Heat through. Ladle into soup bowls. Makes 4 side-dish servings.