Roll out your first sheet of puff pastry. I used a Tupperware croissant maker here, but you can make them normally. Press to mark the portions.

Add the slices of cheese, slices of ham, and Gruyère. Be careful, the cheese will melt a lot and may ooze out of the croissants 🥐. Try to seal the croissants well on the sides 🙂.

Cover with the second sheet of puff pastry. Place a sheet of parchment paper on top, then roll with a rolling pin to reveal the portions.

Remove the parchment paper. Cut with scissors if necessary. If you don't have the device, cut into eight equal parts with scissors. Roll your croissants 🥐.

Preheat your oven to 350°F. Beat the egg. Use a brush to coat each croissant 🥐. If desired, sprinkle sesame and poppy seeds on top.

Bake at 350°F for 25 to 30 minutes, depending on your oven.

Enjoy hot with a side dish or a salad 🥗