Set the Instant Pot to sauté and heat the olive oil. Add beef cubes and sear until browned on all sides, then remove and set aside.
Add onion, carrots, celery, and garlic to the pot. Sauté for about 3 minutes until softened.
Stir in tomato paste and cook for another minute to deepen the flavor.
Return the beef to the pot. Pour in beef broth, add barley, thyme, bay leaf, salt, and pepper. Stir well.
Close the lid, set the valve to sealing, and cook on High Pressure for 25 minutes.
Allow the pressure to release naturally for 10 minutes, then quick release any remaining pressure.
Open the lid, give everything a good stir, and taste to adjust seasoning. Remove bay leaf before serving.
Ladle into bowls, sprinkle with fresh parsley, and enjoy warm.