Cut away any fat still attached to 1 1/2 lbs. beef kidneys. Slice each kidney in half and soak in plenty of cold water for 1 hour.

Transfer kidneys to pot containing 8 cups fresh cold water, bring to boil, simmer several minutes and drain. Repeat 1 or 2 more times, using fresh cold water each time. Drain kidneys.

When cool, cut into thin slices, sprinkle with flour, and brown in 3 Tablespoons lard on all sides. Midway through browning, add 2-3 diced onions, mixing and browning with meat. 

Add 1 cup or more beef bouillon, cover, and simmer on low heat 1-1 1/2 hours or until tender. Replace liquid that evaporates during cooking. Stir in 1-2 Tablespoons tomato concentrate or ketchup, 1 jigger red or white dry wine, 1 heaping Tablespoon sour cream, and salt & pepper to taste.

Simmer 1 minute, stirring to a smooth, pourable sauce. If too thin, sprinkle in a little flour and simmer briefly. Before serving, sprinkle with fresh chopped parsley.