Preheat your oven to 375°F (190°C) and grease a 9×5 loaf pan or line it with parchment paper for easy removal.

In a medium saucepan, melt 2 tablespoons of butter over medium heat. Whisk in 2 tablespoons of all-purpose flour to create a roux. Cook for about a minute until golden and nutty.

Slowly pour in 2 cups of whole milk while whisking constantly to prevent lumps. Let the mixture simmer until it thickens enough to coat the back of a spoon.

Stir in 2 cups of shredded sharp cheddar cheese until fully melted and smooth. Season with 1/2 teaspoon garlic powder, 1/2 teaspoon paprika, and salt and pepper to taste. Fold in 2 cups of cooked elbow macaroni and set the filling aside to cool slightly.

In a large bowl, combine 2 pounds ground beef, 1 cup breadcrumbs, 2 large eggs, 1 finely diced small onion, and 2 minced garlic cloves. Add 1/2 cup milk, 1/2 cup ketchup, 1 tablespoon Worcestershire sauce, 1 teaspoon salt, 1/2 teaspoon black pepper, and 1 teaspoon Italian seasoning. Mix gently with your hands until just combined; avoid overmixing.

Press about two-thirds of the meat mixture into the bottom and up the sides of your prepared loaf pan to form a bowl. Spoon the mac and cheese filling into this meat 'bowl', then cover with the remaining meat mixture. Brush the top with a little extra ketchup.

Bake in the preheated oven for 50-60 minutes, or until the internal temperature reaches 160°F.

Remove from the oven and let the meatloaf rest for 10 minutes before slicing. This resting period helps the mac and cheese center set, making slicing easier and ensuring neat servings.