Meatloaf to me is everything but the kitchen sink.
Whatever you like to put in it.
I'll take the leanest hamburger I can get,
An egg
Milk
A few slices of torn into bits bread (big or small bits)
Chopped up onion and green pepper
Garlic or garlic powder, salt and pepper
A bit of some kind of sauce....crystal hot sauce, BBQ sauce, some kind of Asian.
Mush it all together in a big bowl, let it sit a few minutes. Come back and access the damage. If it's too loose to form a loaf, add some bread or bread crumbs. If it's too dry, add a bit of milk.
Make a loaf and put in a cassarole dish. If you want put a tomato sauce, ketchup or something else on the top.
I don't think it's supposed to turn out the same way twice.
stick a meat thermometer in it and in the oven. After an hour keep checking the thermometer until it's a bit more than rare on the inside, then take it out and let it finish cooking while it's resting. I like it slightly pink in the middle.
BTW, even better than meatloaf, are the meat loaf sammiches afterwards
Mine ends up looking something like this...
If you're all anal and perfect and everything I guess it would look more like this...
Mine looks tastier IMO.