Add basil, parsley, potatoes and broth; bring to a boil.
Reduce heat; cover and simmer for 10 minutes or until potatoes are done.
In a small skillet, melt butter. Add flour, cook and stir 1-2 minutes or until bubbly. Add milk and stir until thickened.
Add to milk mixture to soup along with cheese. Cook and stir until cheese melts.
Remove from heat, add sour cream, if desired.