Mix garlic clove, Sukrin Gold, and parsley in a dish and rub all over pork tenderloin.
Refrigerate for at least 30 minutes, up to overnight.
Turn the IP on to SAUTE setting and add avocado oil. When the IP reaches temperature, sear the outside of the tenderloin on all sides. This should take no more than 5 minutes.
Add water to IP and cook on LOW pressure for 5 minutes. Let pressure NATURAL RELEASE for 10 minutes before opening the steam vent. If your pork tenderloin is more than 2lbs, you may want to let it sit in NR for an extra 1-2 minutes before releasing.
Remove tenderloin to a platter and cover with foil. Let rest for 10 minutes while you make the sauce.
Turn IP to SAUTE setting. When the juices start bubbling, add ACV and xanthan gum. Whisk continuously until the sauce is thickened.
Slice tenderloin into equal-sized medallions. Pour sauce over medallions and serve.