Heat the oven to 350 F (180 C/Gas 4). Line a rimmed baking sheet or pan with foil.
In a large bowl, combine the ground beef, beaten egg, bread crumbs, onion, milk, ¼ cup of Heinz 57, salt, and pepper.
Shape the meat mixture into a loaf and place it in the prepared pan.
Bake in the preheated oven for 1 hour (see note). Carefully pour off excess grease and top with more Heinz 57 Sauce. Return the meatloaf to the oven to 10 to 15 minutes longer.
Allow meatloaf to stand 5 minutes before slicing.