Season roast with salt and pepper. Set Pressure Cooker to High sauté. Once Hot, add olive oil and the beef, browning each side about 3 mins per side. Remove beef pieces and set aside.
Deglaze pot by adding ¼ cup of beef broth and use a wooden spoon to remove brown bits from the bottom.
Add onions and sauté until softened, about 5 mins. Add garlic cloves and sauté for 30 seconds more.
Add remaining beef broth, pepperoncini juice, Italian seasoning, paprika, fennel seeds, red pepper flakes, pepperoncini peppers, and beef to Pressure Cooker. Press Cancel on the pressure cooker, cover and cook on high pressure for 52 mins, then natural release for 20 mins, and then quickly release any remaining pressure.
Remove meat to a baking sheet and use two forks to shred the meat. Pour some of the liquid over the beef until moistened. Reserve the remaining sauce for dipping. Enjoy as a sandwich or any way you prefer your Italian Beef.
These Italian beef sandwiches are delicious when topped with Giardiniera. You can purchase this in many grocery store chains. I also like to top mine with a spicy pepper mix.
For less spicy beef, use fewer pepperoncini.
Serve the au jus sauce on the side for dipping if you like a wet sandwich.