In a large bowl, mix cold mac and cheese with shredded cheddar cheese. The mixture should be thick and hold together. If too wet, refrigerate for 30 minutes.
Using a cookie scoop or spoon, form the mixture into 1.5-inch balls (about the size of a golf ball). Place on a parchment-lined baking sheet.
Freeze the mac and cheese balls for 15-20 minutes to firm up—this helps them hold their shape during cooking.
Set up three shallow bowls: one with flour, one with beaten eggs, and one with panko mixed with Parmesan, garlic powder, onion powder, paprika, salt, and pepper.
Roll each ball in flour, dip in egg (letting excess drip off), then coat generously with the panko mixture, pressing gently to adhere.
Spray each ball liberally with cooking spray on all sides. Preheat air fryer to 390°F.
Arrange balls in a single layer in the air fryer basket without touching. Cook in batches for 10-12 minutes, turning halfway through, until golden brown and crispy.
Let cool for 2-3 minutes before serving. Serve warm with ranch dressing, marinara sauce, or spicy mayo for dipping!