Coat the bottom of the Instant Pot with vegetable oil (this is optional but to prevent the BURN message from appearing).
Add the cube steak, and season. Feel free to layer the steak slices, but season them all.
Add mushrooms, sliced onion, cayenne pepper, salt, and pepper. And finally the beef stock or broth. PLEASE NOTE: IF you want to cook potatoes with the cube steak, slice baby white potatoes in half and add in the pot in this step.
Secure the lid, and make sure that the vent is set on SEALING position. Press on MANUAL or PRESSURE COOK on high pressure, and set at 20 minutes. Allow the pressure cooker to come to pressure (this will take around 10 minutes), and start cooking for 20 minutes.
When the time is up, quickly release the steam. To plate, take the steak out, as long as the veggies. You will be left with the liquids at the pot, you can thicken that to make a gravy by pressing on SAUTE and adding 1-2 tablespoons of cornstarch slurry (see notes), and mixing until the gravy is thickened.
