1/2 pound ground beef 4 tablespoons butter, divided 3/4 cup chopped onion 3/4 cup shredded carrots 3/4 cup diced celery 1 teaspoon dried basil 1 teaspoon dried parsley flakes 1-3/4 pounds (about 4 cups) cubed peeled potatoes 3 cups chicken broth 1/4 cup all-purpose flour 2 to 4 cups shredded Velveeta 1-1/2 cups whole milk 3/4 teaspoon salt 1/4 to 1/2 teaspoon pepper 1/4 cup sour cream

In a large saucepan over medium heat, cook and crumble beef until no longer pink, 6-8 minutes; drain and set aside. In same saucepan, melt 1 tablespoon butter over medium heat. Saute onion, carrots, celery, basil and parsley until vegetables are tender, about 10 minutes. Add potatoes, ground beef and broth; bring to a boil. Reduce heat; simmer, covered, until potatoes are tender, 10-12 minutes.
Meanwhile, in a small skillet, melt remaining butter. Add flour; cook and stir until bubbly, 3-5 minutes. Add to soup; bring to a boil. Cook and stir 2 minutes. Reduce heat to low. Stir in cheese, milk, salt and pepper; cook until cheese melts. Remove from heat; blend in sour cream.