In a large pot melt the butter over medium heat. Add the onions and the celery and sauté for about 4 minutes, until tender. Add the rutabagas and parsnips and stir, then pour in the broth, raise the heat to high and bring to a simmer. Lower the heat to medium and simmer, partially covered, for about 25 minutes until the vegetables are very tender.
Use an immersion blender to puree the vegetables right in the pot, or carefully transfer the vegetables and some of the liquid in batches to a food processor or blender and puree until smooth. Return the soup to the pot, if needed, and stir in the chipotles in adobo and sprinkle in the cheese, stirring as you do this, until the cheese is melted. Add more broth if the soup seems very thick. Add the sour cream and heat just until heated through.
Serve hot, with chopped parsley and a bloop of sour cream, yogurt or crème fraiche and some hot sauce if desired.