Turn the Instant Pot to the saute function. When warm, add the olive oil. When the oil starts to sizzle add the boneless beef stew meat. Season with salt, pepper, and Italian Seasoning then give a good stir. 

Cook the meat until it is browned on all sides and no red/pink color remains.

Add the tomato paste to the pot and stir to coat the meat while also scraping up any browned bits that have formed on the bottom of the Instant Pot. 

Add the beef broth, tomato sauce, and Worcestershire Sauce. Stir to combine.

Now add the garlic, onion, carrots, and potatoes. Stir well to make sure everything is combined. 

Turn the saute function off, and place the lid on the Instant Pot with the vent set to sealing. Cook on high pressure for 35 minutes, then allow the pressure to release naturally for another 10 minutes before performing a quick release. 

In a small bowl, mix together the cornstarch or tapioca starch and cold water until completely combined creating a slurry. Add the slurry to the Instant Pot and stir until the stew thickens slightly. 

Add the flat-leaf parsley to the beef stew and serve immediately.