Bring a large pot of salted water to a rolling boil and cook the elbow macaroni until just shy of al dente (about 1 to 2 minutes less than package instructions). Reserve 1 cup of the starchy pasta cooking water, then drain the pasta and set aside.

While the pasta cooks, prepare the chicken: place each chicken breast between two pieces of plastic wrap and gently pound with a meat mallet or rolling pin to an even thickness about 1/2 inch. Trim if necessary and cut each breast into two cutlets for manageable portions.

Season the chicken cutlets on both sides with salt and freshly ground black pepper. Set up a breading station with three shallow bowls: one with 1 cup all-purpose flour, one with the beaten eggs combined with 2 tablespoons whole milk, and one with the panko breadcrumb mixture (2 cups panko, 1/2 cup grated Parmesan, 1 teaspoon smoked paprika, 1 teaspoon garlic powder, and a pinch of salt). Dredge each cutlet in flour, shaking off excess, dip into the egg wash, then press into the breadcrumb mixture to coat evenly.

In a large heavy skillet, pour enough vegetable oil to reach about 1/4 to 1/3 inch deep and heat over medium-high until shimmering; the oil should reach roughly 350°F if using a thermometer. Fry the cutlets in batches—do not overcrowd—until golden brown and cooked through, about 3 to 4 minutes per side depending on thickness. Transfer finished cutlets to a wire rack set over a baking sheet to drain and hold warm in a low oven (200°F).

Start the cheese sauce in a medium saucepan: melt 4 tablespoons unsalted butter over medium heat. Whisk in 3 tablespoons all-purpose flour and cook for 1 to 2 minutes to form a blond roux without letting it brown. Gradually whisk in 3 cups whole milk and 1 cup heavy cream, smoothing any lumps, then bring the mixture to a gentle simmer until it thickens and coats the back of a spoon, about 5 to 7 minutes.

Remove the sauce from heat and stir in 8 ounces sharp cheddar, 4 ounces mild cheddar, and 2 ounces finely grated Parmesan until fully melted and glossy. Whisk in 1 teaspoon Dijon mustard, 1/2 teaspoon onion powder, 1/4 teaspoon garlic powder, and season with kosher salt and freshly ground black pepper to taste. If the sauce seems too thick, add reserved pasta water a few tablespoons at a time until the desired creamy consistency is reached.

Stir the drained pasta into the cheese sauce, add 2 tablespoons unsalted butter, and fold gently so all the macaroni is coated. Taste and adjust seasoning. If using the optional breadcrumb topping, toss 1/2 cup panko with 2 tablespoons olive oil in a small skillet and toast until golden, then sprinkle over the mac for added crunch.

If assembling as individual trays or a casserole, spoon the mac and cheese into a shallow baking dish or disposable tray. Slice each fried chicken cutlet into thick strips and lay them across the top of the mac. Optionally, finish under the broiler for 2 to 3 minutes to brown the surface and meld the components—watch closely to avoid burning.

Garnish with chopped fresh parsley and a few dashes of hot sauce if desired, and serve immediately so the chicken crust remains crisp and the pasta is warm and creamy.