French Ham and Cheese Croissant Sandwich

Preheat a small non-stick pan over medium-low heat.

Carefully slice the croissant in half horizontally.

Spread Dijon mustard evenly on the bottom half of the croissant.

Layer the ham and Gruyère cheese on top of the mustard.

Place the top half of the croissant over the cheese.

Melt the unsalted butter in the preheated pan.

Place the assembled croissant sandwich in the pan and cook for 2-3 minutes per side, or until the croissant is golden brown and the cheese is melted and bubbly.