Wash and dry the potatoes well. Place the potatoes, olive oil and salt in a large bowl and toss to combine.
1 pound (450 grams) small potatoes, 1 tablespoon olive oil, 1/2 teaspoon salt
Transfer to the air fryer and air fry the potatoes at 400 °F (205 °C) for 15-20 minutes, or until tender.
While they're cooking, stir together the melted butter or olive oil and garlic in a small bowl.
2 tablespoons (28 grams) unsalted butter, 4 cloves garlic
Remove the potatoes from the air fryer and smash them with the bottom of a glass, a rolling pin, a fork or a firm spatula.
Put them back in the air fryer basket in a single layer. If they don't fit, make them in batches.
Bush the potatoes with the prepared garlic butter and air fry for another 10-20 minutes, or until they're golden brown and as crisp as you'd like them.
Sprinkle with grated cheese, if using, and serve.
1/3 to 1/2 cup (30 to 45 grams) Pecorino, Romano or Parmesan cheese
Refrigerate in an airtight container for up to 3 days. See post for reheating options.