Coat meat evenly with a mixture of flour, paprika, and salt.
Heat fat in a Dutch oven or saucepot.
Add onion and cook until soft, stirring occasionally.
Brown meat evenly on all sides in the hot fat; add 3 tablespoons hot water.
Cover and simmer 1 hour, stirring occasionally; add small amounts of water as needed during cooking.
Mix sauerkraut and caraway seed with the meat; add 2 cups hot water.
Cover and simmer 30 minutes, or until meat is tender.
Gradually add about 1 1/2 cups of the cooking liquid to sour cream, blending well.
Stir into mixture in Dutch oven.
Stirring constantly, heat (do not boil) about 5 minutes.