Combine all ingredients in the Instant Pot. Cook on high pressure for about 60 minutes. Natural pressure release for 10-20 minutes.
Shred the beef (it should fall apart very easily when pulled with a fork). Save the broth / juices in the Instant Pot.
Layer each side of your bun with a slice of Provolone and place under the broiler until melty. Top with the beef and giardiniera.
Serve the hot sandwiches with a little dipping bowl of the broth so you can dunk your sandwich in and experience true soppy, cheesy, crusty, tangy Italian beef sandwich bliss.
