01 -
Coat the outside of both bread slices with mayo, spread a little mustard on one inner side, and stack the cheeses on top.
02 -
Set a pan over medium-low heat and let butter melt to grease the surface.
03 -
Cook it covered for 2-3 minutes until it looks golden brown.
04 -
Turn it over, keep it covered, and cook another 1-3 minutes until golden with melty cheese. Turn heat down if it browns too fast.