01 - Cook elbow macaroni in generously salted boiling water until al dente according to package directions. Drain thoroughly and transfer to a large bowl.
02 - Melt butter in a saucepan over medium heat. Whisk in flour and cook for 1 minute, stirring constantly to form a roux. Gradually pour in milk while whisking continuously to prevent lumps. Simmer for 2-3 minutes until sauce thickens and coats the back of a spoon.
03 - Remove saucepan from heat. Stir in shredded cheddar, salt, pepper, and paprika until cheese is completely melted and sauce is smooth. Pour cheese sauce over cooked macaroni and mix until evenly coated. Spread mixture in a single layer on a baking sheet and refrigerate for at least 1 hour until firm and completely chilled.
04 - Scoop chilled macaroni mixture using a 1.5-inch scoop or tablespoon. Roll each portion tightly between palms to form smooth balls. Place formed balls on a parchment-lined baking sheet and freeze for 30 minutes until firm.
05 - Arrange three shallow bowls. Place flour in the first bowl. Beat eggs with milk in the second bowl. Combine panko breadcrumbs and grated Parmesan in the third bowl.
06 - Working with one ball at a time, dredge in flour to coat evenly, shaking off excess. Dip into egg mixture, allowing excess to drip off. Press firmly into panko-Parmesan mixture, coating completely and pressing gently to adhere breading. Return to baking sheet.
07 - Heat vegetable oil in a deep pot or Dutch oven to 350°F. Oil should be 2-3 inches deep. Fry cheese balls in batches of 5-6, turning occasionally, until golden brown and crispy, approximately 2-3 minutes per batch. Do not overcrowd the pot. Remove with a slotted spoon and drain on paper towels.
08 - Transfer fried macaroni balls to a serving platter. Serve immediately while hot and crispy, accompanied by warm marinara sauce for dipping.