Set your oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a bowl, stir together cooked macaroni, cheddar cheese, heavy cream, and garlic powder until the cheese starts to melt and coat the pasta.
In a large bowl, combine ground beef, breadcrumbs, egg, milk, salt, pepper, garlic powder, and onion powder. Mix until just combined—don’t overwork it.
Place half the meat mixture on the prepared baking sheet and shape it into a flat oval loaf with a hollow center.
Spoon the mac ‘n’ cheese into the center, gently pressing it down to keep it in place.
Cover with the remaining meat mixture and press the edges to seal the filling inside.
Brush the top and sides with BBQ sauce for a flavorful, caramelized finish.
Bake for 50–55 minutes, or until the internal temp hits 160°F (71°C) and the top is nicely browned. Let the meatloaf rest for 10 minutes before slicing to lock in juices and keep the filling intact.