Push the "Saute" button on your Instant Pot, and add the olive oil. When hot, add the stew beef to the Instant Pot and sear for five minutes. Turn the cubes and sear the remaining sides, a few minutes per side.
Add the chopped onion and garlic and toss until they begin to soften and turn brown. (It'll happen in just 2-3 minutes because your pot is already so hot!)
Add the beef broth, Worcestershire sauce, thyme, rosemary, and tomato paste. Stir briefly to combine, then cancel the "Saute" mode on your Instant Pot and lock the lid.
Push the "Manual" or "High Pressure" button on your Instant Pot, and set the timer for 20 minutes.
When the timer beeps, let the pot depressurize naturally for about ten minutes while you prep the carrots and potatoes. Peel the veggies (you can leave the skin on your potatoes if you like) and chop into pieces about 3/4 inch thick.
Flip the switch to release the remaining pressure, then open the lid and add the carrots and potatoes. Lock the lid again and push the "Manual" (or "High Pressure") button again, set for 5 minutes.
While the veggies are cooking, mix the corn starch with a tablespoon of water in a small dish.
When the timer beeps, flip the valve to release the pressure manually. Then open the lid and pour in the corn starch slurry. Stir for a minute or two until the stew thickens. Then add the frozen peas and stir until heated through. Enjoy!