Season all sides of the roast with salt, pepper, and garlic powder.
Push “sauté” on instant pot and add the oil.
Sear the meat for about 90 seconds per side.
Add the Worcestershire, vinegar, and broth.
Close the lid, seal the steam valve and cook on the “meat/stew” setting for 100 minutes (for anything bigger than 4 pounds do 110 minutes, for a frozen roast do 120 minutes).
After it is done cooking, let it do a natural pressure release for at least 20 minutes before twisting the steam valve to “venting”.
Shred the meat.
Butter some buns and broil for 45 seconds.
Top the bottom bun with meat, then cheese, and broil for another 45 seconds.
Serve with Au Jus gravy, and if you want to make it next-level, add some sautéed onions and mushrooms. So good!!