In a large mixing bowl, combine the cold mashed potatoes, shredded cheese, grated Parmesan, garlic powder, onion powder, salt, and pepper. Mix thoroughly until all ingredients are evenly incorporated. The consistency should be firm enough to roll into balls. If the mixture feels too soft, refrigerate for 10–15 minutes.

Using clean hands or a small cookie scoop (approximately 1.5 tablespoons), form the mixture into balls about 1.5 inches in diameter. Place them on a parchment-lined tray or plate. If the mixture begins to stick, chilling briefly can help make shaping easier.

In one shallow bowl, place the beaten egg. In a separate bowl, add the breadcrumbs. You may season the breadcrumbs with a small amount of salt, pepper, or dried herbs if desired.

Working with one ball at a time, dip each into the beaten egg, ensuring full coverage. Allow any excess egg to drip off before rolling the ball in breadcrumbs. Gently press the coating onto the surface to help it adhere. Repeat with all remaining balls.

Preheat the air fryer to 375°F (190°C) for approximately 3 minutes to ensure even and consistent crisping during cooking.

Lightly coat the air fryer basket with cooking spray or brush with a small amount of olive oil. Arrange the potato balls in a single layer, leaving space between each for proper air circulation. Lightly spray the tops of the balls as well to promote browning.

Air fry the potato balls for 10–12 minutes, shaking the basket or turning the balls halfway through. They are done when the exterior is golden and crisp and the interior is heated through with melted cheese.

Carefully remove the cooked potato balls from the air fryer using tongs or a slotted spoon. Allow them to cool slightly, then serve warm with dipping sauces such as ranch dressing, marinara, sour cream, or garlic aioli.