Apparently, nobody has called me on this, but I have to step back and retract here, and substitute “dead animal flesh” where I say “any animal product,” to clarify what I meant.
To be fair, grilled cheese sandwiches are often made with American cheese product 
Wimpy wheat bread, please, buttered on the outsides. One slice of American and one slice of nice sharp Swiss, heated up nice and slowly until both sides are crisp and the cheese is total goo. Cut on the diagonal, please. (Though I do two diagonals for my kids and get baby triangles. Easier for them to eat.)
I do believe I make the best grilled cheese in the world. Though I am eager to try Melt in Cleveland sometime. My doctor recommended it, which means it must be very healthy, right?
Oooh, your doctor RECOMMENDED going to Melt? It’s just down the road a bit from me and everyone else I know or am related to has gone, but I haven’t been yet! I do dream about it at night though, sometimes…
Can you get that recommendation in print and send me a copy? LOL I think my doctor has it on his Do Not Go There list until he’s happier with my weight…
OO. That sounds incredibly yummy. You mind if I snag this recipe? Pretty please!
Real Mayonnaise…none of the crappy Miracle Whip. Buttered bread, not oleo.
Pan preheated, but not real hot.
Thinly sliced freshly picked tomato, if possible.
Mayo on a grilled cheese is heresy. Leave off the slime and try Huy Fong Sriracha!
Try Velveeta Mexican. It’s pretty good.
Wheat bread (white or whole grain, doesn’t matter), american and cheddar cheese together, some garlic powder and oregano, crumbled bits of bacon and/or salami, grilled in butter until GBD. Served with cocktail sausages and chicken soup (never liked tomato soup).
Whatever bread and whatever cheese happens to be on hand: usually a whole grain from the bakery down the street, and some cheddar. Occasionally, I like to mince up a fresh jalapeno to add some zip to it.
I have two favorite ways, the real one and the lactose-intolerant pale imitation.
The real way: white sourdough, sharp cheddar, sliced avocado and maybe tomato, grilled without butter or anything in a George Foreman grill.
The pale imitation: white bread, imitation American cheese (Galaxy Veggie American is the best), with mayo instead of butter on the outside, placed in a hot pan on the stove. My family has always used mayo instead of butter, and I really think the flavor is better.
Sourdough or white bread (a dense bread - not something light and fluffy like Wonder “bread”), a slice of medium cheddar and a slice of baby Swiss, and the heck with the purists - put some bacon on it! And real butter, of course…
Ok, white bread or maybe whole wheat, real butter, cheddar cheese. But it’s GOT to be made in a Toas-Tite.
Yes, the Toas-Tite is back! I have an original one, the one my mother made grilled cheese for me using Velveeta. Yeah I said original, because I am that old.
Rye bread with caraway seeds. Butter those breads up and put some pungent swiss inside, then drop sandwich into hot frying pan. Lower a smaller frying pan on top to squish the sandwich and make it fry brown on the down side. Flip. Repeat. Eat.
Grilled. Cheese. Bread and cheese, cooked in butter. I’ll make allowances for those of you just adding condiments, though you should be aware that I am gravely disappointed. Other ingredients make it not a grilled cheese sandwich. Yes, even tomato or onion. This is not to say the results are not tasty–I’m a sucker for the artery-hardening goodness of a grilled bacon and tomato sandwich with cheese–but they should no longer be called “grilled cheese”.
Also, am I the only grilled cheese aficionado who never had tomato soup–milky or otherwise–as a child? Not that I think it’s a bad combination, but it doesn’t hold any special significance to me. If I were to pick a soup to accompany my sandwich, I’d be more likely to go with French Onion.
We never had tomato soup at my house. At my grandparents’ I smeone had tomato soup, but never in conjunction with a grilled cheese.
I’m with you; didn’t want to post my opinion until others have had their say. My grilled cheese is cheese, white bread, and butter. I do not butter the frying pan (I don’t have a good grilling device riht now) - I slather butter on the outside of the bread and double fry it.
Different types of cheeses are always welcome. Served up with a frosty glass of milk.
I want a raclette while hurtling through space in a spaceship.
Thick white bread buttered on the OUTSIDE with real butter, on the inside slabs of Jarslberg or Maasdam cheese.
You home deliver, yes?
I think I started a thread about it before, some years back.
The “best” grilled cheese should be fried in olive oil, not butter.
Do whatever you want with the cheeses and meats. I still maintain that a grilled cheese of any sort has a lot more delicious flavor complexity when fried with olive oil. I grew up on the butter-fried type, and and those are delicious. But for the adult palate - mmmm, olive oil all the way.
Opinions may vary 
Ooo. No we’re talking!
As for olive oil, it’s all good, but I like my grilled cheese with that buttery taste.