Cook the pasta: Bring a large pot of salted water to a rolling boil. Add the macaroni and cook until al dente, about 8 minutes. The pasta should be tender but still firm to the bite, with a slight white core when you break one open. Drain and set aside; do not rinse—the starch helps the sauce cling.

Make the cheese sauce: In a medium saucepan over medium heat, melt the butter until it bubbles and turns a pale golden colour. Whisk in the flour and cook for 2 minutes, stirring constantly—the mixture will smell nutty and look like wet sand. Slowly pour in the warmed milk, whisking vigorously to prevent lumps. Bring to a gentle simmer; the sauce will thicken enough to coat the back of a spoon after about 5 minutes. Remove from heat, stir in the mustard powder, smoked paprika, garlic powder, and the grated cheddar and mozzarella. Stir until the cheese is fully melted and the sauce is smooth and glossy, with a pale golden hue.

Combine and layer: Pour the drained macaroni into the cheese sauce and stir until every piece is evenly coated. The mixture should look creamy and rich, with the sauce clinging to each curl of pasta. Transfer the mac and cheese into a greased 9x13 inch baking dish, spreading it into an even layer. Set aside while you prepare the chicken.

Marinate the chicken: Slice each chicken breast horizontally into two thin cutlets, about 1cm thick. Place them in a bowl and pour the buttermilk over the top. Toss to coat, then cover and refrigerate for at least 20 minutes. This tenderises the meat and helps the coating stick.

Prepare the coating and fry: In a shallow dish, combine the flour, cayenne pepper, onion powder, 1 teaspoon of salt, and ½ teaspoon of black pepper. Remove the chicken from the buttermilk, letting any excess drip off. Dredge each piece in the seasoned flour, pressing firmly so the coating adheres. The chicken should look completely covered in a dry, speckled crust. Heat about 1cm of vegetable oil in a large frying pan over medium-high heat. When a pinch of flour sizzles on contact, add the chicken in a single batch (do not overcrowd). Fry for 3-4 minutes per side, until the coating is deep golden brown and the chicken is cooked through. The crust should feel crisp and shatter slightly when tapped. Transfer to a paper towel-lined plate.

Make the spicy oil: In a small bowl, combine 4 tablespoons of the hot frying oil (carefully spooned from the pan) with 1 tablespoon cayenne pepper, 1 teaspoon brown sugar, and ½ teaspoon garlic powder. Stir until the sugar dissolves—the oil will turn a vibrant, deep red and smell intensely aromatic.

Assemble and bake: Slice the fried chicken into thick strips and arrange them over the mac and cheese in the baking dish. Drizzle the spicy oil evenly over the chicken and pasta. Bake in a preheated oven at 190°C (fan-assisted) for 15-20 minutes, until the edges are bubbling and the top is lightly golden. The cheese sauce should be visibly hot and the chicken coating will have softened slightly while staying crisp.

Rest and serve: Remove from the oven and let the dish rest for 5 minutes before serving. This allows the sauce to settle and thicken slightly, making it easier to serve without it running across the plate.