Fill a pot with water, enough to fit all the potatoes, then bring to a boil. Add 1 tsp of salt.
Transfer creamer potatoes into the pot and boil for 15-20 minutes or until potatoes are cooked. Larger potatoes may take 25-30 minutes.
Discard the water and rinse the potatoes with cold water. Pour into a colander and allow to cool for about 5 minutes.
Transfer the potatoes onto a tray. Using a masher (or the bottom of a mug) smash the potatoes until flattened, but still in one piece. Thinner potatoes will be crispier. Thicker potatoes will possess crispy edges with a fluffy interior.
Pour 1 tbsp melted butter onto the potatoes.
Sprinkle 1/4 tsp salt, 1/4 tsp garlic powder and several cracks of black pepper. Adjust according to taste.
Spray air fryer basket or rack and surface of smashed potatoes with cooking oil. Transfer smashed potatoes onto the basket/rack and air fry at 400°F for 12-15 minutes or until desired crispiness. Keep in mind that times and temperatures may vary depending on your air fryer.
Top with parmesan cheese and sliced cilantro. Serve immediately!