Cut the dough into 8 triangles. Make a small cut in the center of the base of the triangles. Place the ham and cheese in the center and roll up from the base to the tip, shaping the ends of the croissants.
Brush with beaten egg yolk and add a little more grated cheese on top.
Bake at 200°C (392°F) for 15-20 minutes or until golden brown.
