Season stew meat with salt, pepper and Italian seasoning
Add olive oil to the Instant Pot. Using the display panel select the SAUTE function.
When oil starts to sizzle, brown the meat on all sides. Meat will not be cooked through. Do not crowd the pot--you may have to work in batches. Transfer browned meat to a bowl, but leave as much liquid as possible in the pot.
Add garlic, onions, carrots and celery to the pot. Continue to sauté for 3-4 minutes (if it gets too dry, add additional 1 tbsp of olive oil)
Add beef broth to the pot and deglaze by using a wooden spoon to scrape the brown bits from the bottom of the pot.
Add beef back to the pot along with Worcestershire sauce, tomato sauce and potatoes.
Turn the pot off by selecting CANCEL, then secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL function*. Use the +/- buttons and program the Instant Pot for 30 minutes.
When the time is up, let the pressure naturally release for 15 minutes, then quick-release the remaining pressure.
Mix together the cornstarch with 2 tbsp cold water in a small bowl and stir into the stew until thickened.
Notes
*If your Instant Pot does not have a MANUAL function, use the Pressure Cook function.