Creating Mac and Cheese Meatloaf Casserole is simple if you follow these steps:

1. Preheat your oven to 350°F (175°C).
2. Cook the Macaroni: In a pot of boiling water, cook the macaroni until al dente. Drain and set aside.
3. Prepare the Meatloaf Mixture: In a large bowl, mix together the ground beef, breadcrumbs, shredded cheese, egg, onion, garlic, Worcestershire sauce, salt, pepper, and parsley.
4. Form the Meatloaf: Shape the meat mixture into a loaf and place it in a greased baking dish.
5. Bake the Meatloaf: Bake in the preheated oven for 30 minutes.
6. Make the Cheese Sauce: In a saucepan, melt the butter over medium heat. Whisk in the flour and cook for 2 minutes. Gradually whisk in the milk, mustard powder, and paprika. Continue stirring until the mixture thickens. Remove from heat and stir in the shredded cheese until melted.
7. Combine Mac and Cheese: Pour the cooked macaroni into the cheese sauce and mix until well combined.
8. Layer in Casserole: After the meatloaf has baked for 30 minutes, pour the mac and cheese over the meatloaf, spreading it evenly.
9. Return to Oven: Bake for an additional 25 minutes or until the cheese is bubbly and golden.
10. Cool: Remove from the oven and let it cool for about 10-15 minutes before slicing.

These simple steps will guide you in creating this amazing casserole that effortlessly delights.