Preheat oven to 350°F (175°C) and grease a 9x13 inch baking dish with butter or cooking spray.

Cook elbow macaroni according to package directions until al dente, drain well and set aside.

In a large bowl, combine ground beef, diced onion, minced garlic, breadcrumbs, eggs, milk, Worcestershire sauce, salt, pepper, oregano, and paprika. Mix thoroughly until well combined.

Press the meat mixture evenly into the bottom of prepared baking dish, creating uniform layer.

Bake the meatloaf base for 20 minutes, then remove from oven and carefully drain any excess grease.

In a large saucepan, melt butter over medium heat and whisk in flour to create a roux. Cook for 2 minutes, stirring constantly.

Gradually whisk in milk, ensuring no lumps form. Continue cooking and stirring until sauce thickens, approximately 5-7 minutes.

Remove sauce from heat and stir in cheddar, mozzarella, and Parmesan cheeses until completely melted. Season with salt, garlic powder, and cayenne pepper.

Combine cooked macaroni with cheese sauce, stirring until every piece of pasta is well coated.

Spread mac and cheese mixture evenly over partially cooked meatloaf base, creating thick, even layer.

Sprinkle additional cup of cheddar cheese over top of casserole, ensuring even coverage.

Return to oven and bake for additional 25-30 minutes, until cheese is golden brown and bubbly.

Remove from oven and let rest for 10 minutes before serving. Garnish with fresh parsley and paprika.

Cut into squares and serve hot, ensuring each portion includes both meatloaf base and mac and cheese layers.