i haven't had a real meatloaf in a long time. we only use turkey.
i make mine with a pound of ground turkey. get the 93/7, not the extra lean all white meat ground turkey. it's too dry.
add milk, 2 eggwhites (eggwhites make it lighter and more tender than a whole egg) , ketchup, s&p, chopped fresh parsley, seasoned breadcrumbs, and diced raw sweet onions. the sweeter the onion the better.
free form it in a glass baking dish, not working or compressing the meat too much. top with more ketchup and roast at 350.
for something different, nix the ketchup, and use mustard. then, top the formed loaf with whole grain mustard and press fennel seeds into it.