01 - Cook the macaroni according to package instructions. Drain thoroughly and set aside.
02 - In a saucepan over medium heat, melt the butter. Whisk in the flour and cook for 1 minute, stirring constantly to create a smooth paste.
03 - Gradually whisk in the milk and cook until thickened, about 2–3 minutes. Stir in the cheddar and mozzarella cheeses until completely melted and smooth. Season with salt and pepper.
04 - Add cooked macaroni to the cheese sauce, stirring to coat evenly. Spread the mixture onto a baking sheet and refrigerate for at least 2 hours, or until firm enough to handle.
05 - Once chilled, scoop about 2 tablespoons of macaroni mixture and roll into balls. Place on a parchment-lined tray.
06 - Arrange three shallow bowls: place flour in the first bowl, whisk eggs with 1 tablespoon milk in the second bowl, and place panko breadcrumbs in the third bowl.
07 - Roll each ball in flour, shaking off excess. Dip into the egg mixture, then coat thoroughly 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 occasionally until golden brown on all sides. Remove with a slotted spoon and drain on paper towels.
10 - Serve hot with your favorite dipping sauce such as marinara, ranch, or spicy ketchup.