Preheat your oven to 350°F (175°C) and lightly grease a loaf pan or line it with parchment for easy cleanup.
In a large mixing bowl, add the ground beef, stuffing mix (straight from the box, dry), eggs, chopped onion, a good pinch of salt and pepper, and ¼ cup ketchup.
Pour in 1 cup of water to help the stuffing hydrate and blend smoothly with the beef. Use your hands or a sturdy spoon to mix everything together until well-combined but not over-mixed.
Transfer the meat mixture into the prepared loaf pan, pressing it down gently to fill the corners and shape evenly.
In a small bowl, blend together about ¼ cup ketchup and 2 tablespoons brown sugar (adjust to taste for more sweetness or tang). Spread this over the top of the meatloaf to form a sweet glaze.
Bake, uncovered, for 50–60 minutes, or until the meatloaf is cooked through and the glaze is bubbly and caramelized. If using a thermometer, check for an internal temperature of 160°F.
Let the meatloaf rest 10 minutes before slicing, so it stays juicy and is easier to cut.
