Cook prunes in 2cups water for 5 minutes. When soft enough to remove pits, do so.
Put prunes back into water; add sausage pieces and lemon slice. Cook until prunes are almost cooked.
Mix sour cream and flour, dilute with a little of the cooking liquid, and whip. Pour sour-cream mixture into pot. Simmer for 5 minutes longer and serve.
Replace sausage with diced smoked pork tenderloin; cook it in ½cup water with juice of 1 lemon, juice of 1 orange, grated rind of ¼ lemon, grated rind of ¼ orange, 1teaspoon sugar and 1tablespoon wine vinegar. When pork is almost done, add dried prunes and cook until dish is completely finished.