In a large pot, melt 1 tablespoon butter or margarine over medium heat: cook and stir vegetables and beef , until beef is brown.
Stir in basil and parsley. Add broth and potatoes. Bring to a boil, then simmer until potatoes are tender, about 10-12 minutes.
Melt the remainder of butter and stir in flour. Add the milk, stirring until smooth.
Gradually add milk mixture to the soup, stirring constantly. Bring to a boil and reduce heat to simmer. Stir in cheese. When cheese is melted, add sour cream and heat through. Do not boil.