Brown ground beef. Add the onion and cook unitl soft. Add the carrots, celery and garlic and cook about 5-10 minutes, add the broth, potatoes and seasonings. Bring to a simmer, cover, and cook 20 minutes or so.
Make a white sauce. Melt the butter, slowly add the flour, stirring constantly and cook 2 minutes over medium low heat. Slowly whisk in the milk, stirring constantly. Turn the heat up and simmer a few minutes until thick. Stir into the soup. Add the cheese and stir until melted. Just before serving, stir in the sour cream.
Goes great with biscuits.