Remove the roast from the fridge to remove the chill. Slice the onions and add oil to the Instant Pot. Set to “Saute” and allow oil to heat with the lid removed. Add the onions and sauté about 10 minutes, stirring occasionally, or until onions begin to caramelize.

While onion are sautéing, cube the roast into 2-3″ sections. Lightly season with pepper and steak seasoning. Remove the onions from the Instant Pot, add a small amount of oil if needed, and add the beef. Use long handled tongs to turn the cubes, allowing them to sear on each side, about 10 minutes. Once seared evenly, add the onions back in. Pour in the beef stock, Worcestershire sauce, soy sauce, garlic, and fresh herbs. Seal the Instant Pot lid and change the settings to “Meat/Stew”. Set for 50 minutes, allowing a few extra minutes for pressure to build.

Once timer goes off, allow a 20 minute natural release before venting to release remaining pressure. In the meantime, slice hoagie buns in half. Lightly butter each side and toast face down on a flat skillet or in a toaster oven.

Once pressure is fully released, remove the beef from the Instant Pot and transfer to a bowl or platter. Use two forks to shred the beef. Strain the remaining liquid through a fine mesh sieve or colander into a mason jar or gravy boat and reserve cooking liquid for au jus.

Spread the whole grain mustard on the bottom of each hoagie bun. Add the shredded beef roast, then top with thinly sliced green onions and one slice of provolone cheese (cut in half to fit the bun). Add the top bun, then serve immediately with reserved au jus for dipping.