In a large saucepan, saute onion and celery in butter until tender. Add potatoes and broth; bring to a boil. Reduce heat; cover and simmer for 10-15 minutes or until potatoes are tender.
Puree in small batches in a blender until smooth; return to the pan. Stir in the cheese, milk, pepper and paprika. Cook and stir over low heat until the cheese is melted.
Garnish with croutons and parsley.
Please note that some ingredients and brands may not be available in every store.