Press Sauté button and click the adjust button to go to Sauté More function on the Instant Pot. Wait until the indicator says “hot”. You can prep the ingredients while the pressure cooker is heating up.
Season one side of the chuck steak generously with kosher salt and freshly ground black pepper. Add olive oil in pressure cooker. Ensure to coat the oil over whole bottom of the pot.
Carefully place the seasoned side of chuck steak in pressure cooker. Generously season the other side with kosher salt and freshly ground black pepper. Brown for 6 – 8 minutes on each side without flipping. Remove and set aside in a large mixing bowl.
While the chuck steak is browning in the Instant Pot, mix 1 tablespoon Worcestershire sauce, 1 tablespoon light soy sauce, 1 tablespoon fish sauce, 1 tablespoon tomato paste with 1/2 cup chicken stock.
Add olive oil in pressure cooker if necessary. Add thinly sliced small onions and shallots and sauté until softened. Add minced garlic cloves and stir for roughly 30 seconds until fragrant. Add in the quartered mushrooms and sauté for another 3 minutes. Season with salt and freshly ground black pepper if desired.
Pouring in 1/2 cup Guinness draught, completely deglaze the bottom of the pot by scrubbing the flavorful brown bits with wooden spoon. Pour in the remaining 1/2 cup Guinness draught.
Add 1 bay leaf, 2 sprigs thyme, 1 sprig rosemary, 70% dark chocolate, russet potato chunks, carrot chunks and chicken stock mixture in the pot. Mix well.
Close lid and pressure cook on Manual at High Pressure for 4 minutes. When time is up, Quick Release the pressure. Open the lid carefully.
While the vegetables are pressure cooking, cut the chuck steak into 1.5 – 2 inches stew cubes. Place all chuck stew meat and the flavorful meat juice back in the large mixing bowl. Add 1 flour in mixing bowl and mix well with the stew meat.
Remove half of the carrot chunks & all mushrooms from pressure cooker and set aside. Place beef stew meat and all its juice in pressure cooker. Partially submerge the beef stew meat in the liquid without stirring, as you don’t want too much flour in the liquid at this point.
Layer a stainless-steel bowl filled with halved Yukon gold potatoes on top.
Close lid and pressure cook on Manual at High Pressure for 32 minutes. When time is up, allow for 10 minutes Natural Release. Turn off the heat by pressing Cancel. Release the remaining pressure. Open the lid. Remove and set aside the stainless bowl.
Discard bay leaf and the herbs. On Sauté function, breakdown the mushy russet potatoes with wooden spoon. Stir to thicken the stew. Add sautéed mushrooms, and the previously set aside carrots in the pot. Taste and season with kosher salt and freshly ground black pepper if necessary.
It may be a good idea to drain & transfer the potatoes to a larger mixing bowl. Mash the cooked potatoes with a potato masher. Mix in whole milk and unsalted butter. Season to taste with salt & pepper.
Garnish with Italian Parsley. Serve the Irish beef stew with mashed potatoes. Enjoy!