To start, combine the flour, salt, and pepper in a large mixing bowl. Make sure you mix the ingredients well to distribute the flavors evenly.
Next, pat each piece of beef dry with a piece of paper towel.
Then, place it inside the flour mixture and make sure it's covered well. Shake off any excess flour and set it aside. Repeat this process with all the beef pieces.
Next, heat 2 tablespoons of oil in a large frying pan. Use medium-high heat to preheat the pan.
Once heated, add some flour-coated beef pieces and leave them to fry for 3-4 minutes on each side. The pieces should become beautifully browned. But keep in mind, they will not be cooked through, and that's perfectly fine.
While the beef is browning, heat the remaining tablespoon of oil in a separate frying pan over medium heat. Add the diced onions and minced garlic. Leave them to saute for about 5 minutes.
Once the beef is browned and the onion mixture has been sauteed, remove both from the heat.
Next, combine the sauteed onion and garlic mixture, mushroom soup, beef broth, and bay leaves in the pressure cooked. Carefully add the pan-fried beef so the liquids don't splash.
Close the pressure cooker lid. Cook on high pressure for 60 minutes. Once it beeps, carefully release the pressure and remove the beef.
In a separate large bowl while the meat is still hot, pull the beef with two forks into smaller pieces. Set it aside.
Whisk together the cornstarch and water in a small bowl until it forms a smooth slurry. Slowly add some of the leftover gravy (in the pressure cooker) to the slurry to thin it out.
When it's thinned, add the leftover gravy and slurry mixture to a saucepan. Bring it to a boil while whisking often. This will create a thicker gravy.
Once boiling, add the shredded beef and lower the heat slightly. Leave the mixture to simmer for 5 minutes.
Finally, serve your delicious pulled roast beef with some gravy on flatbread, in a bun, or over freshly cooked rice.