Pre-heat the oven to 350 and line a sheet tray with aluminum foil. Get out a loaf pan. Combine the beef, breadcrumbs, onion soup mix, eggs, garlic powder, salt and pepper in a bowl and use your clean hands to thoroughly mix it together. Press the mixture firmly into the loaf pan and put the full loaf pan on the sheet tray. In another bowl, mix the HP sauce or ketchup, brown sugar, ground mustard and nutmeg together into a thick glaze. Spread the glaze evenly over the meatloaf and bake it for an hour and a half. An hour gets it to just slightly pink in the center. If you would prefer well done, let it go for an extra 15-20 minutes. Let it cool slightly, then serve immediately!