01 -
Preheat the oven to 175°C. Lightly grease a 23×33 cm baking dish.
02 -
In a large mixing bowl, combine ground beef, diced onion, breadcrumbs, egg, milk, salt, and black pepper. Mix until just incorporated.
03 -
Press the meat mixture evenly into the bottom of the prepared baking dish to form a single layer. Bake for 20 minutes.
04 -
While the meatloaf bakes, cook macaroni in salted boiling water according to package directions until al dente. Drain and set aside.
05 -
In a medium saucepan over medium heat, melt butter. Whisk in flour and cook for 1 minute, stirring constantly. Gradually add milk, whisking continuously until the sauce thickens, about 3–5 minutes. Stir in salt, black pepper, paprika, and dry mustard.
06 -
Add 150 g of shredded cheddar cheese to the sauce and stir until melted and smooth. Gently fold in the cooked macaroni until evenly coated.
07 -
Spread the macaroni and cheese mixture over the partially baked meatloaf layer. Sprinkle the remaining 50 g cheddar cheese evenly over the top.
08 -
Return the dish to the oven and bake for 25 minutes, or until the cheese is golden, melted, and bubbling.
09 -
Let the casserole rest for 5–10 minutes before slicing and serving.