If using chuck roast and not already cut stew meat, cut the beef into 1.5-2 inch cubes.
Heat 1 tablespoon oil in the Instant Pot using the sauté mode. When the pot is hot, add half the beef. Sprinkle with half the salt and pepper.
Brown the beef on the first side, don’t move it for about 5 minutes or until browned and easily releases from the bottom of the pot. Flip over and brown the other side. Remove to a covered container to keep warm.
Add the rest of the oil and the remaining beef to brown as you did with the first half. Return the other half of the beef back into the pot.
Pour in the broth, garlic, tomato paste, dried seasonings and stir to combine.
Add the onions, carrots, radish, and mushrooms. Turn off sauté mode.
Close the lid and cook on manual mode at high pressure for 35 minutes. It will take about 10-15 minutes for the pressure to come to temperature. Once the timer ends, allow the pressure to naturally release for 10 minutes. Then using a long wooden spoon, push the steam valve to release pressure quickly.
Carefully open the lid, stir beef stew and decide if you’d like a thicker broth. If so, sprinkle the glucomannan over the stew, stir to combine.
Serve with a sprinkle of fresh parsley and enjoy immediately!