Cut boneless, beef chuck roast into 4 equal sized pieces. Season with salt, pepper, garlic powder, onion powder, and Italian seasoning.
Turn on your pressure cooker and push the “Sauté” button. When the liner is hot, add the olive oil and swirl around the bottom to evenly coat. Sear the meat on all sides until browned.
Once browned, remove from pressure cooker and transfer to a plate. Press the “Cancel” button and pour the beef stock and fish sauce into the liner. Use a wooden spoon to scrape all of the cooked bits off the bottom. Do Not Skip This Step or you will risk a “Burn” notice.
Place the trivet in the liner, then add the browned meat and onion slices.
Place the lid on your Instant Pot and twist to lock. Check to make sure the valve is in the “Sealing” position, press the “Manual” or “Pressure Cook” on (High) pressure, and adjust the time to 60 minutes. Newer models will display as 1:00.
While the meat is cooking, slice the bell peppers and toss them with salt, pepper, and garlic powder. Sauté the pepper slices in a skillet with olive oil until softened and lighter in color. Set aside and keep warm.
When the pressure cooker beeps, allow to naturally release the pressure for 15 minutes then press the valve open to release the remaining pressure. Note: Always let the pot do a natural pressure release (NPR). This means letting the pressure drop on its own for 15 to 25 minutes after cooking. Natural release keeps the beef succulent, letting muscle fibers relax instead of tightening up and losing juices.
Use two forks, a pair of sturdy tongs, or even a stand mixer with the paddle attachment (for large batches). Pull along the grain for long, tender pieces. For a more rustic texture, break some sections into shorter shreds.
Top with the bell peppers and serve over cauliflower rice, mashed potatoes or a green salad for Whole30 and Paleo. Served on toasted bun with sliced provolone cheese for a traditional sandwich. Garnish with pepperoncini and/or giardiniera.
Notes
For Italian beef sandwich: Slice the roll in half without cutting all the way through. Place under the broiler for a few minutes to toast. Place your beef on the roll, top with giardiniera, pepperoncini peppers, then ladle the hot juices over the top.
How to store:
Chill fast: Let beef cool, then pack into airtight containers with enough juice to keep it moist.
Fridge: Keeps well for 3-4 days.
Freezer: Up to 6 months with minimal loss of flavor.
To reheat:
Simmer beef and jus in a saucepan or in the Instant Pot on “Sauté.”
Keep the beef in its juices to prevent drying.
For sandwiches, warm portions and pile onto hot rolls so the bread soaks up all the good stuff.