For the recipe you will need:
for the test:

flour – 450g
salt – 1/2 tsp
fat or oil (cubed) – 225g
parsley (chopped, curly) – 4 tbsp.
For filling:

potatoes (peeled and diced) – 500g
green onions (finely chopped) – 2 pcs.
parsley (chopped curly) – 4 tbsp.
cheese – 50g
egg (boiled, finely chopped) – 1 pc.
egg (yolk) – 1 pc.
cream (fatty) – 2 tbsp.
salt, black pepper (ground) – to taste.
To make Parsley Pies:

Sift flour and salt into a bowl. Knead flour with fat or butter with your fingertips until fine crumbs form. In a blender, beat parsley with yolk and 2 tablespoons of cold water. Put this into the flour mixture and mix, adding enough cold water to make a firm dough. Wrap in foil and refrigerate 30 minutes. Preheat oven to 180C.

Cut the dough into 4 pieces. Form each into a ball and roll out on a floured surface to form a circle the size of a dessert plate. Transfer to a baking sheet. Mix potatoes with onion, parsley, cheese and egg. Beat egg yolk with cream and add to potato mixture. Season. Divide between the circles of dough, leaving around 1 cm to the edge. Moisten the edges of the dough around the filling. Connect the edges. Pierce with a fork and top with beaten egg yolk if desired.

Bake for 45-50 minutes, or until pastry is softly golden on the outside. Serve warm or cold with English mustard.