Spray the bottom of a 6-quart slow cooker. Put cubed steak in slow cooker.
Sprinkle with au jus packet and beefy French onion soup mix packet.
Pour in water and cream of chicken soup. Stir.
Cover slow cooker and cook steak on low for 8 hours.
Thirty Minutes before serving, in a small bowl, whisk together cornstarch and 1/4 cup of juices. Stir mixture into crock pot. Turn the setting to high and cook for 30 minutes or until gravy is thickened.