Pat the pork chops dry with paper towels and season both sides generously with garlic powder, salt, and pepper. Set your Instant Pot to SAUTÉ mode and add the olive oil, allowing it to heat until shimmering, about 1-2 minutes. Working in batches if needed to avoid crowding, sear the pork chops for 2 minutes per side until they develop a golden-brown crust—this creates flavor through the Maillard reaction. Remove the seared chops to a plate and set aside. I like to use thick-cut pork chops because they stay juicier during pressure cooking and won't dry out.

Pour 1 cup of beef broth into the pot and use a wooden spoon to scrape up all the browned bits stuck to the bottom—this is liquid gold for flavor. Add the sliced onions, mushrooms, cream of mushroom soup, and parsley, stirring gently to combine. Return the seared pork chops to the pot, nestling them into the sauce and vegetables. The liquid should partially cover the chops but doesn't need to submerge them completely, as the pressure cooking will create plenty of steam.

Close the Instant Pot lid, ensure the valve is set to SEALING, and cook on HIGH pressure for 15 minutes. This gentle, moist cooking method keeps the pork chops tender and allows the flavors to meld together. When the timer goes off, allow the pressure to release naturally for 10 minutes, then carefully switch the valve to VENTING to release any remaining steam before opening the lid.

Carefully remove the cooked pork chops to a serving platter using tongs, leaving the cooking liquid and vegetables in the pot. In a small bowl, whisk together the remaining 1/4 cup of cold beef broth with the cornstarch until smooth—this slurry prevents lumps from forming in the sauce. Set the pot back to SAUTÉ mode and bring the liquid to a gentle boil. Slowly pour the cornstarch mixture into the boiling liquid while stirring constantly until the sauce thickens to a rich, glossy gravy, about 2-3 minutes. I find that pouring the slurry slowly and stirring constantly gives you the smoothest gravy without any lumps.

Arrange the pork chops on a serving plate with your choice of sides—mashed potatoes, egg noodles, or rice work beautifully. Spoon the mushroom gravy and vegetables generously over the top. Serve immediately while the pork chops and sauce are still hot.