Season the beef. Pat the beef dry and season with salt, pepper, paprika, and cayenne.
Sear the beef. Set the Instant Pot to Sauté and wait until it reads Hot. Add the oil and sear the beef in batches until browned. Don't overcrowd the pot. Transfer the browned beef to a plate and set aside.
Cook the onion. Add the diced onion to the pot and cook for 2–3 minutes, until it begins to soften. Press Cancel.
Deglaze the pot. Pour in the red wine, beef stock, and Worcestershire sauce. Scrape the bottom of the pot thoroughly to loosen any browned bits.
Pressure cook the beef. Return the beef to the pot and add the garlic. Spoon the tomato paste over the top and add the thyme. There's no need to stir. Close the lid, set the valve to Sealing, and cook on High Pressure for 20 minutes.
Release the pressure. When the cooking time ends, let the pressure release naturally for 10 minutes, then carefully release the remaining pressure. Open the lid and remove the thyme stems.
Add the vegetables. Add the potatoes, carrots, celery, and mushrooms. Close the lid and cook on High Pressure for 6 minutes.
Natural release again. Let the pressure release naturally. If you're short on time, wait at least 10–15 minutes before carefully releasing any remaining pressure.
Thicken the stew. Mix the cornstarch and water in a small bowl until smooth. Set the Instant Pot to Sauté, stir in the slurry, and simmer for 2–3 minutes, until the gravy thickens.
Season and serve. Taste and adjust the salt and pepper as needed. Serve hot.
Notes
***This recipe was tested with a 6-quart Instant Pot***
Brown the beef in batches so it sears instead of steaming.
Scrape the bottom of the pot thoroughly after adding the wine and broth to help prevent a burn warning.
Cut the vegetables into large, even pieces so they hold their shape under pressure.
Better Than Bouillon Roasted Beef Base can be used for the beef stock. Taste before adding extra salt since different stocks and bouillon vary in saltiness.
Let the pressure release naturally for at least 10 minutes rather than immediately quick releasing.
If the finished gravy is too thick, stir in a little additional beef broth.
Store leftovers in the refrigerator for up to 4 days or freeze for up to 3 months.