In a small bowl, mix the melted butter, olive oil, garlic powder and parsley flakes. Set aside.
Carefully push a skewer through the centre of each potato.
Using a small, sharp knife, carefully cut the potatoes into a spiral. Hold the knife at a slight angle and slowly turn the potato as you cut around. The spiral slices should be about ¼ inch wide.
After you have cut around the entire potato, gently pull the slices apart along the length of the skewer.
Brush the melted butter over the potatoes paying attention to getting it between all of the spirals.
Place the potatoes in the air fryer basket, set the temperature to 390°F and cook for 20-22 minutes until the potatoes are crispy and golden.
Remove from the potatoes from the air fryer and sprinkle with sea salt flakes. If desired, garnish with parmesan cheese or chopped herbs.