Preheat oven to 160ºC . Heat fat in a deep heavy pot. Cook the onions, peppers, and garlic until the onions are limp and transparent. Add paprika has lost its raw taste. Add beef and remaining ingredients except sour cream. Stir well to combine. Simmer in preheated oven for 1.5 to 2 hours or until the meat is tender. Adjust oven temperature during cooking time so contents of pot remain at a simmer. Serve in shallow soup bowls with a tablespoon of sour cream atop each serving.