01 - Cook the macaroni according to package instructions. Drain and set aside.
02 - In a saucepan over medium heat, melt the butter. Whisk in the flour and cook for 1 minute.
03 - Gradually whisk in the milk and cook until thickened, about 2–3 minutes. Stir in the cheddar and mozzarella cheeses until smooth. Season with salt and pepper.
04 - Add cooked macaroni to the cheese sauce, stirring to coat. Spread the mixture onto a baking sheet and refrigerate for at least 2 hours, or until firm.
05 - Once chilled, scoop about 2 tablespoons of macaroni mixture and roll into balls. Place on a parchment-lined tray.
06 - Place flour in one bowl, whisk eggs and 1 tablespoon milk in a second, and panko breadcrumbs in a third.
07 - Roll each ball in flour, dip into the egg mixture, then coat with panko breadcrumbs. Repeat for all balls.
08 - Heat 2 inches of vegetable oil in a deep pot to 350°F.
09 - Fry the balls in batches for 2–3 minutes, turning until golden brown. Drain on paper towels. Serve hot with your favorite dipping sauce.