If we're building, and not buying, I'd offer the following:
good ground beef with some fat in it
NO, repeat: NO, powders, liquids, or other tschidt beyond a bit of salt and pepper, added to the raw meat to adulterate the flavor
cooked very carefully to avoid any charring
a good-quality bun (soft and fresh without and damned seeds stuck onto it)
a slice of good cheese that doesn't turn to liquid goo, but just sort of settles gently onto the patty
a slice of good tomato - one with very little snot
a leaf or two of good, green lettuce - not the hard white stuff
some white goop wouldn't hurt
ketchup (Heinz, of course, the rest is a poor imitation.)
mustard - good old, regular yellow French's, not some fancy-assed thing that overpowers everything else
Wait just a darn minute... you say this..
NO, repeat: NO, powders, liquids, or other tschidt beyond a bit of salt and pepper, added to the raw meat to adulterate the flavorThen follow up with this?
some white goop wouldn't hurt
ketchup (Heinz, of course, the rest is a poor imitation.)
mustard - good old, regular yellow French's, not some fancy-assed thing that overpowers everything else 
