In a medium-sized bowl, mix leftover mashed potatoes with crumbled bacon, chives or green onion, salt, and pepper. If desired, add garlic powder.
With floured hands, scoop mashed potato into the palm of your hand. I used a small cookie scoop to get 2" balls. Flatten into a disk and add a cube of cheese to the center. Carefully form into a ball with the cheese completely covered with potatoes.
Add flour to a shallow dish. Scramble egg and 1-2 tablespoons of milk in another dish, and add breadcrumbs and grated parmesan to a third shallow dish. Dip each mashed potato ball in flour, then egg, then breadcrumbs. Repeat dipping back into the egg and then breadcrumbs again to give it an extra crispy coating.
Add a single layer of mashed potato balls to the air fryer basket. Lightly spray balls with cooking oil.
Cook at 370 degrees Fahrenheit for 4 minutes, shake the basket, spray with additional oil as needed, and continue baking for 2-3 more minutes until golden brown. Be careful not to overcook because the cheese will begin to ooze out of the balls. Serve with ranch dipping sauce.
Notes
VariationsIf your mashed potatoes do not have any flavors added to them besides the traditional salt and pepper, I recommend turning them into garlic mashed potatoes by adding a ½ teaspoon of garlic powder.Another great variation is adding a ranch seasoning packet to the potatoes because ranch-seasoned potatoes are to die for!