Now, a sandwich can be made with toasted bread, certainly, but in that role it's normally slathered with mayonnaise, mustard, or something of that nature rather than being buttered.
Exception: grilled cheese sandwiches are often buttered, though with those they typically have the butter on the outside. On the inside is either nothing or (my preference) mayonnaise.
If you can get it, Duke's Mayo is just absolutely bonkers. I also really like the Trader Joe's organic mayo.
Also, since I'm deeply invested in grilled cheeses, more recommendations:
I use a ratio of 1 part gruyere, 1 part sharp or extra-sharp cheddar. I also really like a little parmesan or pecorino, but it tastes less "classic grilled cheese," so might not be for everyone.
Cooking method:
- heat pan to medium
- put mayo on one side of two pieces of bread
- put the first piece of bread into the pan, mayo side down (it should sizzle lightly)
- heap your cheese on top of this piece, and press it down onto the bread a little
- after 2 minutes, take the other piece of bread and put it mayo side up onto the top of the cheese. flip the sandwich (so that the fresh mayo is now down).
- 2 more minutes and you're good to go. serve with tomato soup (naturally) and a little ranch if you're a degenerate like me.
I suspect it depends on the ingredients ... you need a bread that goes well with the oil and have to be very careful on not oversoaking it.
[0] https://www.nordichouse.co.uk/enamel-butter-dish-p-4219.html
https://www.nytimes.com/interactive/2015/04/14/dining/field-...
If there's one food America knows how to do in many variations, all delicious to varying degrees, it's the sandwich.