Traditional Russian Kidney-Pickle Soup, also known as Rassolnik, is a hearty and flavorful soup made with beef kidneys, pickles, and barley. This soup is a popular dish in Russian cuisine and is often enjoyed during the winter months. The kidneys add a rich and meaty flavor to the soup, while the pickles provide a tangy and slightly sour taste. To make the soup, simmer beef kidneys with onions, carrots, and barley until tender. Add pickles, pickle brine, and herbs for additional flavor. Serve the kidney-pickle soup hot with a dollop of sour cream and fresh dill.