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