Tomato-Potato Soup

10 medium potatoes, peeled and cubed
1 cup tomato puree
4 to 5 tblsp flour
3 tblsp sour cream
milk
salt to taste

Cover potatoes with water. Add a little salt and boil until tender. Dilute tomato puree with a little water and add to potatoes. Mix in a small bowl or cup, flour and just enough milk to form a paste. Stir until smooth. Add sour cream; stir until blended, then add more milk. Stir and pour into soup. Simmer for 20 minutes.Serve Hot.