Slice the top off each potato lengthwise. Each “lid†should be about 1/2 inch thick at its thickest point. (Discard “lids†or reserve for another use.) Pour one cup of water in the Instant Pot and insert the steam rack. Place the potatoes on the rack. Secure the lid, making sure the vent is closed. Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 12 minutes. When the time is up, quick-release the pressure. Carefully remove the potatoes from the pot to a cutting board and allow to cool slightly. Scoop out the center of the potato flesh, being careful not to pierce the skin and to leave enough “structure†so the potato stands up easily on its own. Roughly mash half the scooped out centers in a medium bowl. Don’t worry if it’s not completely cooked. (Set aside the other half of the potato centers for some other use, or discard.) Add eggs, ham, onion, parsley and 2 tbsp of the cheese to the potatoes and stir to combine. Fill each potato shell with the egg mixture and top with remaining cheese. Place the potatoes on the steam rack again, then secure the lid, making sure the vent is closed. Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 6 minutes. When the time is up, quick-release the pressure. (Optional) Set the potatoes under the broiler to brown the cheese. Serve hot topped with freshly ground pepper and a sprinkling of salt.