In a large mixing bowl, add the beef, breadcrumbs, eggs, onion, garlic powder, parsley, Italian seasoning, salt, pepper and bbq sauce. Use your hands to work/squish everything together until the mixture's evenly combined.
Spray a meatloaf pan with non stick cooking spray. Add two slices of white bread to the bottom of your meatloaf pan, to line it & suck up the grease. Take half of the meat mixture into your hands and shape it into a loaf. Place it on top of the bread in the pan, and press the center down and the sides up against the dish (leaving 1" sides all around) to create a bowl shape in the middle.
In a separate mixing bowl, add the mac and mozzarella. Stir together until evenly combined. Spread the pasta evenly out into the depression in the meatloaf boat. Top it with the remaining meat mixture, spreading until completely covered and using your fingers to pinch close all the way around and seal.
Bake at 350 degrees for 40 minutes.