Thoroughly wash/scrub the potatoes. You can peel them if you prefer, but leaving the skin on adds extra crispiness and nutrients.
Bring a pot full of water to a boil over high heat. Add a tablespoon of salt. Once water starts boiling, add the cleaned potatoes.
Reduce the heat to medium and simmer until the potatoes are fork-tender but not falling apart, about 15 – 20 minutes for small potatoes, slightly longer for medium ones.
Once done, drain the potatoes thoroughly in a colander and let them sit for a few minutes to steam dry. This step is crucial for crispiness!
Once the potatoes are cool enough to handle but still warm, place them on a clean cutting board or a sturdy, flat surface.
Using a potato masher, the bottom of a sturdy glass/bowl, press down on each potato until it flattens to about ½ to ¾ inch thick. Be careful not to completely mash them into a purée; you want them smashed with some texture and craggy edges.
Brush each smashed potato nicely from both sides with olive oil or melted butter. Sprinkle with garlic powder, black pepper, and salt.
Preheat your air fryer to 400°F (200°C) for 3-5 minutes (if your model requires preheating).
Arrange the smashed potatoes in a single layer in the air fryer basket. Do not overcrowd the basket. Cook in batches if necessary to ensure proper air circulation and maximum crispiness. Overcrowding will steam the potatoes instead of crisping them.
Air fry for 20 minutes, flipping them halfway through (around the 10-15 minute mark). Continue cooking until they are deeply golden brown and wonderfully crispy on both sides.
Once golden and crispy, carefully remove the smashed potatoes from the air fryer. Transfer to a serving platter. If desired, sprinkle with fresh chopped herbs like parsley, chives, or rosemary for a burst of freshness.
Serve smashed potatoes with a dipping sauce of choice.