I have heard rumblings about people putting mayonnaise on the outside of their bread used for grilled cheese sandwiches and it being the best thing ever. I haven’t had the guts to try it myself. Has anybody heard the rumors and/or done this? How did it turn out?
I’m a big advocate of the hybrid approach: mayo on the bread, butter to grease the pan. The mayo adds a crisp (not crunchy) texture and browns wonderfully, but is helped by the flavor of the butter.
Some butter on the inside of the bread is also great.