01 -
Preheat the oven to 375°F (190°C) and line a baking sheet with parchment paper.
02 -
Spread Dijon mustard and mayonnaise on the inside of each croissant half, if using.
03 -
Layer two slices of ham and two slices of cheese inside each croissant. Close the croissants and place them on the prepared baking sheet.
04 -
Lightly brush the tops of the croissants with melted butter.
05 -
Bake for 12-15 minutes, or until the cheese is melted and the croissants are golden brown.
06 -
Remove from the oven and serve warm.