Saute 2 large onions. Seer 3 pounds london broil 1 piece. Remove from roasting pan and cut up in small pieces. Pour sauteed onions into roasting pan and return meat into roasting pan. Simmer for short period and add 3 tablespoons vinegar, 1 tablespoon sugar and 3 bay leaves. Season (salt and pepper). Simmer for about 15 minutes Add boiling water to cover meat and cook for 1 1/2-2 hours. Thicken and last add 2 tablespoons sour cream. Do not cook any more.