Preheat the oven to 375°F, line a baking sheet, and place one puff pastry sheet on it.
Spread Dijon mustard lightly, then layer ham, cheese, and herbs evenly.
Top with the second pastry sheet and press gently to align.
Cut into tree shapes, slice side strips, and twist to form branches.
Brush with beaten egg and sprinkle lightly with salt and herbs.
Bake for 18 to 22 minutes until puffed and golden.
Brush hot pastries with melted butter.
Transfer to a platter and garnish lightly before serving.