# Directions:
01 - Arrange bread slices on a clean work surface.
02 - Spread a thin, even layer of mayonnaise on one side of each bread slice.
03 - If using, spread a thin layer of Dijon mustard on the opposite sides of two bread slices.
04 - Place two slices of cheese between two bread slices with mayonnaise sides facing outward; repeat for second sandwich.
05 - Warm a nonstick skillet over medium-low heat.
06 - Place sandwiches mayonnaise side down in the skillet and cook for 3 to 4 minutes until golden brown.
07 - Flip sandwiches and cook another 3 to 4 minutes, pressing gently with a spatula, until golden and cheese is melted.
08 - Remove sandwiches from skillet, allow to rest for 1 minute, then slice and serve immediately.