Cheeseburger Soup

1/2 lb. ground beef
3/4 c. chopped onion
3/4 c. shredded (or chopped up, whatever) carrots
3/4 c. chopped celery
1 tea. each dried basil and parsley flakes
4 T butter, divided
3 c. chicken broth (I just use water and chicken bouillon cubes)
4 c. diced peeled potatoes (if the family is lucky...usually I don't peel them)
1/4 c. flour
1/2 lb. American cheese, cubed (though I usually just buy the not wrapped kind in the sandwich aisle and layer them on top of the soup when needed)
1 1/2 c. milk
3/4 tea. salt
1/2 tea. pepper
1/4 c. sour cream

In a big pot, brown beef, drain and set aside. In the same pan, saute' onions, carrots, celery, basil, and parsley in 1 tablespoon of butter until vegetables are tender, about 10 minutes. Add broth, potatoes, and beef; bring to a boil. Reduce heat, cover, and simmer for 10-12 minutes, until potatoes are tender. Meanwhile, in a small skillet, melt the remaining butter. Add flour; cook and stir about two minutes or so, making a roux. Add to soup; bring to boil. Cook and stir 2 minutes . Reduce heat to low. Add cheese, milk, and salt and pepper. Cook and stir until cheese melts (do not boil). Remove from heat; blend in sour cream.