For the ham and cheese bites, chop the ham very finely and also cut or grate the cheese into small cubes.
In a bowl, mix cheese and ham well with all ingredients. On a floured work surface, roll out puff pastry thinly, cut into squares and coat them with the filling.
Now fold the dough over each other to make triangular pouches. Press the edges of the pastry firmly together, if necessary using a fork.
Meanwhile, preheat the oven to about 180 degrees and line a baking tray with baking paper. After placing the pockets on the baking tray, brush them with egg yolk and bake for about 13-18 minutes until golden brown.
Let the ham and cheese bites cool a bit before serving, as the melted cheese is very hot.