Add olive oil to the Instant Pot. Using the display panel select the SAUTE function.
When oil gets hot, add meat and onions. Brown the meat on all sides, 4-5 minutes.
Add broth and wine to the pot and deglaze by using a wooden spoon to scrape the brown bits from the bottom of the pot.
Add mushrooms and stir to combine. Add a steam rack or riser on top of the mushrooms. (Use the one that came with your pot,)
Place potato cubes into a steamer basket and place basket on the steam rack or riser.
Turn the pot off by selecting CANCEL, then secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 15 minutes.
When the time is up, quick-release the pressure.
Carefully remove the potatoes to a bowl. Add butter, sour cream and salt and mash to desired consistency.
Remove steam rack or riser and stir in worcestershire.
In a small bowl, mix together 1/2 cup of pot liquid and cornstarch. Stir into the pot until thickened, returning to SAUTE mode as needed. Adjust seasonings.
Serve beef and mushrooms over mashed potatoes. Garnish with chopped italian parsley (optional)