I have an “official” recipe that I kinda sorta follow sometimes if I feel like it, but usually I have way more hamburger than the amount called for in the official recipe (we buy one cow a year and have most of it, minus the excellent cuts [about which I am very specific] ground into hamburger). This is how I made it last night:

2-1/2 lb hamburger
1-1/2 c bread crumbs (combined my own dried/crumbled with boughten seasoned)
1 c milk
1/2 c yellow onion, chopped
2 eggs
2 T Worcestershire sauce (this is the key to a good meatloaf, IMO)
1 tsp salt
1 tsp dry mustard
1/2 tsp pepper
1/2 tsp ground sage

Mix all ingredients (knead it with your hands as you would bread dough) and put into a springform pan. Put on an aluminum-foil-lined cookie sheet. Cook at 350F for 1 hour.

Add ketchup as needed.

NOTE: For low-carb version, substitute bread crumbs with chopped mushrooms (not the kind from the can).

If you’re easily squicked about meat and the eating thereof, you may stop reading right here.

I love steak tartare. If you don’t know what that is, it’s raw ground sirloin with egg and capons and a bunch of spices in it. I eat this meatloaf raw once I get all the spices worked in and settled. Sometimes I’ll add a little extra Worcestershire sauce. Poor woman’s tartare.