Combine all ingredients except sour cream and noodles and parsley in slow cooker. Cover; cook on Low heat setting for 6 to 8 hours, or High heat setting for 4 to 5 hours or until beef is tender. Stir in sour cream just before serving. Serve over hot noodles; sprinkle with parsley.
*Substitute 2 teaspoons beef bouillon granules.
TIP: The au jus concentrate can be found in the meat, condiment, savory sauces and marinades or dry seasonings packet section of most large supermarkets. Sold in small plastic bottles, this dark-colored concentrated liquid is most often used to make the juicy sauce for French Dip sandwiches. It adds great “beefy” flavor!