Season the beef cubes with salt and pepper.
Set the Instant Pot to Sauté mode and add the vegetable oil.
Brown the beef in batches, removing each batch to a plate when done.
Add onions and garlic to the pot, sautéing until softened.
Return the beef to the pot and add carrots, potatoes, celery, beef broth, diced tomatoes, tomato paste, thyme, rosemary, and bay leaves.
Close the lid, set the valve to sealing, and cook on High Pressure for 20 minutes.
When the cooking time is up, allow for a 10-minute natural release, then quick release any remaining pressure.
Open the lid and stir in the frozen peas.
If the stew is too thin, mix cornstarch with 1/4 cup cold water and stir into the stew. Use the Sauté function to simmer until thickened.
Taste and adjust seasonings as needed.
Serve hot and enjoy!