01 - Pat chuck roast dry using paper towels. Coat all sides evenly with kosher salt and black pepper.
02 - Activate 'Sauté' mode on the Instant Pot. Add a drizzle of oil. Sear the roast for 3 to 4 minutes per side until deeply browned; transfer to a plate.
03 - Add quartered onions and minced garlic to the pot. Sauté for 2 minutes until aromatic.
04 - Stir in tomato paste, scraping up any browned bits from the pot. Add beef broth and Worcestershire sauce, combining thoroughly.
05 - Return the roast to the Instant Pot, sprinkle in dried thyme and rosemary, and place bay leaves into the pot.
06 - Arrange carrots and halved baby potatoes on top of the beef.
07 - Secure the lid. Set valve to 'Sealing'. Select 'Manual/Pressure Cook' on high pressure for 60 minutes.
08 - Allow the pressure to release naturally for 10 to 15 minutes, then perform a careful quick release of any remaining pressure.
09 - Transfer beef and vegetables to a serving platter. Remove and discard bay leaves.
10 - Activate 'Sauté' mode. Whisk together cornstarch and cold water to form a slurry; pour into pot and simmer for 2 to 3 minutes until gravy thickens.
11 - Carve the beef roast. Serve slices alongside vegetables and ladle with warm gravy.