Add all ingredients except heavy cream and Parmesan cheese to pressure cooker and stir.
Close and lock lid, set pressure cooker to "steam/veggies", and press "start/stop".
When done, quick release and make sure all pressure is released before opening lid.
Carefully open lid and stir in heavy cream and Parmesan cheese. Set pressure cooker to "sear", press start/stop and allow sauce to thicken to desired consistency.
Check seasoning and add salt and pepper if needed. Stir in parsley and serve hot.