I added about half an onion, sauteed to keep the meatloaf moist during baking.
Unlike a loose hamburger patty that relies on direct, high-heat pan-searing to build a crust, ground beef baked in a loaf pan or shaped freely on a sheet tray requires internal moisture retainers to prevent it from turning into a dry brick. Achieving this balance in a compact oven demands careful attention to binding agents and fat content.
When removing gluten by omitting standard wheat bread crumbs, substitute an equal volume of finely crushed gluten-free crackers or rolled oats to maintain structure without sacrificing the binding capability needed to hold the meat together during slicing. Overworking the protein matrix when mixing the beef, egg, and dairy components will create a dense, rubbery final texture, so gently fold the ingredients until just combined before transferring the mixture to a 350-degree oven for its 60-to-90-minute bake.