Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame-seed bun.
BUT CHECK IT OUT: these lyrics don’t even mention the defining feature of a Big Mac: that it’s a double-decker burger. There’s a slice of bunstuff between the two patties! That’s really important! THAT’S WHAT MAKES IT A BIG MAC.
The Big Mac Song lyrics are actually describing a different burger! They are describing a mere double cheeseburger. Or, as you might know it:
A Double Whopper With Cheese.
Your argument is that they’re failing to mention the bunstuff in the middle but then you clearly missed the tomato in the middle of the Double Whopper With Cheese.
Please revise your theory before wasting my time any further.
1 - Burger King’s slogan is “Have It Your Way” and one way you can have a Double Whopper Meat Sandwich your way is without tomato. OH SNAP
2 - Also, I’d argue that the Big Mac song is the minimum sufficient standard for a Big Mac: you can get extras put on it if you want, like oh I don’t know TOMATO
King Jerry Lawler’s “SlamBurgers” Restaurant and Menu 
Despite what that sign says, Jerry Lawler did not own the SlamBurgers restaurant. “The King” merely gave the real owner the rights to use his likeness and name for a cut of the profits, and the burger shop changed its entire menu to be wrestling based.
“‘Home Made’ Chili” from a white-labeled pro-wrestling diner? Nommy nom nom!
I want this to still exist sooo bad.
Man, I didn’t even notice the archaic spelling of “Gibroni” last time I reblogged this. It’s like looking at old government documents that say “Congreff”.