Start by assembling the shortcrust ingredients in a bowl.
Work the dough out with your hands until smooth. Keep aside for 30 min. in the fridge.
In the meanwhile make the filling by cooking the Bechamel - white sauce. In a pan add the butter and heat up. Add the flour and keep on stirring on low heat until incorporated.
Continue to add the milk and keep on stirring with the whisk, or the content will burn and stick at the bottom.
Season with salt, pepper, and nutmeg and keep on stirring! Once the sauce is done keep it off the heat.
Add the shredded chicken pieces to the sauce and cut your mushrooms into slices and add them to the Bechamel Sauce as well.
Season the content with the remaining herbs, such as Parsley, Thyme and Marjoram. Keep aside.
Take out your dough from the fridge and make two halves. One should be a bit bigger compared to the other.
Grab the bigger piece and roll it 3 millimeters thick out.
Place your pie shape over your rolled out dough and calculate 5 ½ centimeters extra. Cut it circular out. That's going to be your pie bottom. Pick up the cut out pie bottom and place it carefully into the mold.
Preheat the oven to 200 Celsius .
Now roll out your second smaller dough to a 3 millimeter thick pie cover. Keep aside.
Return to the pie bottom and mold, and grab the pot with the chicken mushroom sauce. Pour the whole filling into the pie.
Grab the Pie cover dough and place it on top. Seal it at the borders and remove the surplus dough, if there is any. Make a hole at the center and push a paper roll into it. That's called a "chimney", it prevents the pie to blow up in the center and helps it to keep its shape. Poke a couple of small holes into the cover as well.
You can decorate your pie with remaining dough by rolling the rest out and cutting out shapes such as leafs, diamonds etc. After cutting out place them carefully on top of the pie top and press them a bit down so that they don't fall off.
Bake the Pie at 200 Celcius for about 30 minutes or until golden.