Prepare the Pressure Cooker: Heat up your pressure cooker (Instant Pot: press Sauté button and click the adjust button to go to Sauté More function) over medium-high heat. Make sure your pot is as hot as it can be (Instant Pot: wait until the indicator says HOT).
Brown Beef Brisket: Trim off excess fat on the beef brisket. Then, generously season the beef brisket with kosher salt and pepper. Add 1 tablespoon (15ml) olive oil in the pot. Ensure to coat the oil over the whole bottom of the pot. Sear both sides of brisket for roughly 5 minutes per side without constantly flipping. Then, remove beef brisket and set aside on a chopping board.
Make Chicken Stock Mixture: While the brisket is browning in the pressure cooker, combine unsalted chicken stock, Worcestershire sauce, regular soy sauce, fish sauce, and tomato paste in a medium bowl.
Saute Vegetables: Add 1 tablespoon (15 ml) of olive oil to the pot, then add onion and season with kosher salt and pepper. Cook until the onions are tender and brown, then add garlic and stir until fragrant. Add chopped celery, carrot, and a pinch of kosher salt and pepper, then cook for 2 minutes.
Deglaze: Add a dash of sherry wine and completely deglaze the bottom of the pot with a wooden spoon. Then, allow the wine to reduce. Add the Chicken Stock Mixture to the pot.
Cut Beef Brisket: Cut the beef brisket into 1 – 1.5 inches cube chunks, then toss with flour.
Pressure Cook Beef Stew: Add the beef briskets chunks and make sure the briskets are spread out, so each piece can soak the stock mixture. Don’t stir the beef briskets as you don’t want too much flour to get into the stock mixture. Then, add bay leaves and rub dried thymes against your fingers and sprinkle them in the pot. Add the potatoes on top. Pressure Cook at High Pressure for-Electric Pressure Cooker: 70 minutes, then Natural Release
-Stovetop Pressure Cooker: 55 minutes, then Natural Release
Serve Pressure Cooker Beef Stew: Add salt and pepper to taste. Serve immediately with pasta, rice, or just eat it as is.
Optional step: For more texture, add additional parboiled potatoes, chopped carrots, and chopped celery to the stew. Cook until the vegetables are tender.