Cheeseburger Soup

This soups is so good. All my kids loved it and that's saying a lot considering what picky eaters I have. I adapted it from The recipe critic

1 pound ground beef
1 onion chopped
1 cup diced carrots
1 cup chopped celery
1 teaspoon basil
1 teaspoon parsley
4 tablespoons butter
4 cups chicken broth
4 cups peeled and diced potatoes
1/4 cup flour
16 ounces cubed Velveeta cheese
1 1/2 cups milk
3/4 teaspoons salt
1/2 teaspoon pepper
1/4 cup sour cream

1. Brown the beef in a sauce pan. Drain the grease and set aside.
2. In the same sauce pan, add tablespoon butter, chopped onions, chopped celery, parsley and basil. Saute until tender about 5 minutes. 
3. Add broth, diced Potatoes and beef and bring to a boil. Reduce heat cover and simmer for 10-15 minutes or until tender.
4. In a small skillet melt 3 tablespoons butter and whisk in the flour. Add ti the soup and bring to a boil. cook and stir 2 minutes. Reduce heat to low.
5. Stir in the cubed Velveeta cheese, milk, salt, and pepper, Cook and stir until cheese melts. Remove from heat and blend in sour cream.