Make the mac & cheese: Cook macaroni until al dente. Meanwhile, melt 2 Tbsp butter in a saucepan, whisk in flour, then gradually add half-and-half until thickened (about 2 minutes). Stir in cheddar cheese until smooth, then season with salt and pepper. Combine with pasta. Chill mixture in a sprayed 9×9 pan for at least 4 hours until firm.

Shape & freeze: Once chilled, cut the set mixture into squares and roll each into a ball. Return to the fridge if too soft; refrigerate or freeze until firm for easy handling.

Bread the balls: Set up a dredging station: dip each chilled ball first in beaten egg + milk, then coat with panko. Repeat for an extra crispy crust if desired.

Air fry: Preheat your air fryer to 360–380 °F. Lightly spray the breaded balls with olive oil or nonstick spray. Arrange in a single layer (no overcrowding). Air-fry for 8–10 minutes, flipping halfway—until golden brown and crispy.

Serve: On each plate, spread a thin layer of marinara, place the crispy mac balls on top, sprinkle with Parmesan, and serve immediately.