Add ground beef to the inner pot of the Instant Pot. Cook on saute mode until the ground beef has browned.
Add in sliced potatoes, beef stock, and seasonings. Stir together.
Close the Instant Pot lid and turn the pressure valve to sealing. Set for a manual high pressure time of 2 minutes and do a quick pressure release when the cooking time has finished.
Turn on the saute mode. Add in milk and cheddar cheese, stirring to mix in and melt the cheese. Mix together water and cornstarch in a small bowl. Pour in topot and stir in to thicken homemade helper.