01 - Spread a thin layer of unsalted butter on one side of each bread slice.
02 - Arrange 2 bread slices, buttered side facing down, on a clean work surface.
03 - Spread 1 tablespoon honey mustard onto the unbuttered side of each bottom bread slice.
04 - Place 2 slices smoked ham and 2 slices Swiss cheese onto each prepared bread slice.
05 - Top with remaining bread slices, buttered side up.
06 - Heat a nonstick skillet or griddle over medium heat. Place sandwiches on the surface and cook for 3 to 4 minutes per side, pressing gently with a spatula, until bread turns golden and cheese is fully melted.
07 - Remove sandwiches, allow to rest for 1 minute, then slice in half and serve while warm.