Preheat oven to 375°F (190°C). Line a baking sheet with parchment paper.
Slice each croissant in half horizontally. Spread the bottom half with a thin layer of Dijon mustard and honey.
Layer 2 slices of ham and 1 slice of cheese inside each croissant, then place the tops back on.
Arrange the filled croissants on the prepared baking sheet.
In a small bowl, mix melted butter, garlic powder, onion powder, and poppy seeds. Brush the tops of the croissants with the mixture.
Bake for 10-12 minutes, or until the croissants are golden and the cheese is melted.
Garnish with chopped parsley if desired and serve warm.