01 -
Preheat your oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish.
02 -
In a large mixing bowl, combine the ground beef, breadcrumbs, Parmesan cheese, milk, ketchup, egg, garlic powder, onion powder, salt, and black pepper. Mix until fully combined. Press the mixture evenly into the bottom of the prepared baking dish to form the meatloaf layer.
03 -
In a pot of boiling salted water, cook the elbow macaroni according to package instructions until al dente. Drain and set aside.
04 -
In a saucepan over medium heat, melt the butter. Stir in the flour and cook for 1-2 minutes to create a roux. Gradually whisk in the milk, mustard powder, salt, and black pepper. Continue cooking, stirring frequently, until the sauce thickens (about 5-7 minutes). Remove from heat and stir in the shredded cheddar cheese until melted and smooth.
05 -
Add the cooked macaroni to the cheese sauce, stirring until the macaroni is well coated.
06 -
Spread the mac and cheese mixture evenly over the meatloaf layer in the baking dish. Sprinkle the additional shredded cheddar cheese and breadcrumbs on top.
07 -
Bake in the preheated oven for 25-30 minutes, or until the cheese is bubbly and golden brown.
08 -
Allow the casserole to cool for a few minutes before slicing. Serve warm.