First, prepare the onions and carrots and set aside.
Select "sauté" on the Instant Pot and let it warm up. Add 2 Tablespoons of the butter and allow to melt.
While butter is melting, season the roast with salt and pepper.
Add the beef to the pot and brown on all sides for 3-4 minutes per side. Remove browned meat and put on a plate and set aside.
Add the other 1 Tablespoon of butter to the Instant Pot and let it melt. Then add onions and carrots to Instant Pot and cook for about 3-4 minutes until softened and lightly browned. Stir in the water or beef stock and the garlic powder. Scrape the bottom of the pot with a wooden spoon, releasing all the browned parts, which adds more flavor.
Add the roast back to the pot with the vegetables.
Put on the lid, lock it, and set vent to sealing. Use the "manual" button to set the time to 60 minutes on high pressure.
When cooking time is up, allow pressure to naturally release for 15-20 minutes. Then do a quick release.
Serve with mashed potatoes or mashed cauliflower.