Pressure cookers cut about three-fourths off the cooking time of smothered pork chops and make them a one-pot meal -- like a slow cooker does, except faster. An airtight lid and pressure valve make pressure cookers different than other pans, but you can still use them to sear and saute, a fundamental step in smothered chops. If you brown the ingredients and build the gravy in the pressure cooker before securing the lid, you can have smothered pork chops ready to go in 15 minutes of active cooking time.
Dredge the pork chops in seasoned flour and heat a few tablespoons of oil in the pressure cooker on the stove, using medium-high heat. Sear the pork chops on both sides until golden brown and set aside.
Add a little more oil to the pressure cooker and saute the vegetables until caramelized. Smothered pork chops typically call for sliced onions and chopped garlic, but you can substitute other alliums, such as leeks or shallots, or add vegetables, such as bell peppers and mushrooms, if you like; they'll cook at about the same rate in the pressure cooker.
Sprinkle 1 tablespoon of all-purpose flour over the vegetables and fat for every 2 pork chops and cook for about 1 minute, stirring frequently. Pour 2 parts chicken stock and 1 part buttermilk in the pressure cooker and whisk until incorporated. You need 1 cup of liquid for every 2 pork chops.
Season the stock and buttermilk with salt and pepper, then return the pork chops to the pressure cooker and secure the lid. Let the pressure build until the cooker reaches high pressure, then lower the heat on the stove to medium-low.
Pressure-cook the pork chops for 6 minutes, then remove the cooker from the heat. Run cold water over the top of the cooker until you hear the safety lock release.
Transfer the pork chops to the serving dish and smother them with the sauce.