In a large saucepan, saute the onion and celery in butter until tender. Add
the broth and baking soda. Combine the cornstarch and water; add to pan. Bring to a boil; boil for 2 minutes, stirring occasionally. Reduce heat. Add sauerkraut, cream and corned beef; simmer and stir for 15 minutes. Add
cheese; heat until melted. Add salt and black pepper. For serving garnish with croutons if desired.