Chop bacon. Set aside. Cook onions in drippings over medium high heat until transparent. Add flour stirring to prevent lumps. Cook for 3-5 minutes until mixture just begins to turn golden. Add broth (it helps if it is warm) gradually, stirring constantly with whisk until thickened. Reduce heat to simmer and add potatoes, cream, bacon, parsley, garlic, basil, Tabasco, and black pepper. Simmer 10 minutes. DO NOT BOIL. Add cheese and green onion. Stir until cheese melts.
This can be made ahead up to the point of adding the cheese and onion. Reheat the soup very slowly and gently. Be careful that it does not boil. Then add the cheese and green onion. Of course if there is any leftover it reheats beautifully. I have never tried freezing it.