Turn the Instant Pot on to the sauté mode. Add olive oil and let it heat up.
Season the beef cubes with salt and pepper, then add them to the pot. Brown the beef on all sides, about 5-7 minutes. Remove the beef and set aside.
In the same pot, add the chopped onion and sauté until translucent, about 3 minutes.
Add minced garlic and cook for another 1 minute until fragrant.
Stir in the tomato paste, thyme, smoked paprika, and Worcestershire sauce (if using). Combine everything well for about 1-2 minutes.
Pour in the beef broth, scraping up any browned bits from the bottom of the pot to prevent burning.
Return the browned beef to the pot, along with the sliced carrots and diced potatoes.
Close the lid of the Instant Pot, making sure the pressure valve is set to 'sealing'.
Set the Instant Pot to cook on high pressure for 35 minutes.
Once cooking is complete, let the pressure release naturally for 10 minutes, then switch to quick release for any remaining pressure.
If you prefer a thicker stew, combine cornstarch and water in a small bowl to make a slurry, then stir it into the stew and set the Instant Pot to sauté mode again. Let it simmer for a few minutes until thickened.
Notes
Serve the beef stew in deep bowls, garnished with fresh parsley for a pop of color. Pair it with crusty bread on the side for a complete meal.