TO MAKE IN THE INSTANT POT:

Add beef back to Instant Pot (with onions) and add mushrooms, garlic powder, onion powder, dried thyme, rosemary, bouillon cube, Worcestershire sauce, bay leaf, pepperoncinis, and 1 1/2 cups beef stock.
Cover and select “Meat/Stew” setting. Cook on high pressure for 35 minutes. Once cooking time is up, let pressure release naturally for 10 minutes before switching the pressure release valve to “venting” to release any remaining pressure.
Turn on “Sauté” setting. Stir cornstarch into 3 tablespoons water, then stir into cooking liquid in Instant Pot.
Let simmer until gravy thickens, then season to taste with salt and pepper. Enjoy!