# Directions:
01 - Arrange bread slices on a clean 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 side of two bread slices.
04 - Place two slices of cheese between two bread slices with mayonnaise-coated sides facing outward; repeat for second sandwich.
05 - Preheat a nonstick skillet over medium-low heat.
06 - Place sandwiches mayo-side down in skillet; cook 3 to 4 minutes until golden brown.
07 - Flip sandwiches and cook other side for 3 to 4 minutes, pressing gently with spatula, until bread is golden and cheese is melted.
08 - Remove sandwiches from skillet, let rest 1 minute, slice, and serve immediately.