8 med. potatoes, diced
1 sm. onion, optional
2 tbsp. butter
2 tbsp. flour
1 c. cold water
1/2 pt. sour cream

Cook diced potatoes with onion in a deep pot with enough water to cover potatoes. In skillet, brown flour in melted butter. Then pour in the cup of cold water and stir until smooth.

Pour this mixture into cooked potatoes and boil a few minutes. Take a dipper of this broth and mix with the sour cream in a bowl. Blend well. Now add this to the potato soup. This prevents curdling.