Preheat Air Fryer to 350 F.
Spray Air Fryer basket with non stick spray.
Take about 2 tablespoons of cold mac & cheese and roll into a ball about 2”. Add milk a little at a time, if needed for the mac and cheese to stick. Repeat until all the macaroni and cheese has been used.
In a bowl, combine flour with your favorite spice mix and mix well.
In a separate bowl, beat the buttermilk and egg until well combined.
In another bowl, have the Panko breadcrumbs ready.
Take each ball of macaroni and cheese and first roll it well in the flour, shaking off any excess.
Then dip it into the buttermilk combination, rolling it around so that it is well coated.
Lastly, roll it in the Panko, shaking off any excess.
Place in prepared Air Fryer Basket.
Cook for 10 minutes, until golden brown.
Serve with Marinara sauce.