Wash potatoes thoroughly since we won’t be peeling the skin. Cut into bite sizes and add to the pot. Also add chopped onion and 3 cups of water. Cover and seal the valve and cook on high pressure for 3 minutes. When done, quickly release all pressure and remove the potatoes from the pot and allow it to cool off.
While the potato is cooking, grab a small glass bowl and add in mayo and olive oil, mix to combine and set aside. Also slice the olives in half and chop the parsley.
When the potato is almost completely cooled off, add the olives, capers and feta cheese, season with oregano, red pepper flakes, sea salt and pepper to taste. Add the mayo and gently fold. Top with fresh parsley.