Preheat your oven: Begin by preheating your oven to 375°F (190°C) to ensure it’s ready for the croissants.
Prepare the croissants: Take each croissant and slice them in half horizontally, creating a top and bottom for your delightful sandwiches.
Add the mustard: On the bottom half of each croissant, spread a generous 1 tablespoon of Dijon mustard, ensuring even coverage for a flavorful kick.
Layer the ham: Place the sliced ham evenly over the mustard-coated halves, making sure to cover as much surface area as possible for maximum taste.
Add Swiss cheese: Top the ham with slices of Swiss cheese, layering them generously to create a melty, cheesy experience.
Season it up: Scatter the finely chopped fresh rosemary over the cheese layer, then sprinkle a little salt and freshly cracked black pepper to enhance all the flavors.
Reassemble the croissants: Carefully place the top half of each croissant back on top of the cheesy ham filling, creating a scrumptious sandwich.
Brush with butter: Use a pastry brush to apply the melted butter to the tops of the croissants, giving them a rich, golden color when baked.
Prepare for baking: Arrange the assembled croissants on a baking sheet lined with parchment paper to prevent sticking and for easy cleanup.
Apply egg wash: Once all croissants are assembled, brush the tops with the beaten egg to provide a glossy, appetizing finish once baked.
Bake to perfection: Place the baking sheet in the preheated oven and bake for 12-15 minutes, or until the croissants are golden brown and the cheese has melted beautifully.
Cool and serve: After baking, remove the croissants from the oven and allow them to cool for a few minutes before serving to prevent any burns.
Notes
Serve on a rustic wooden board with extra Dijon mustard for dipping.