Season the pork loin with salt and pepper and fry it in the clarified butter. Put aside.
Now sauté the sliced onion, the sliced mushrooms, the bacon and the chopped parsley in the pan as well. And finally fold in the creme fraiche.
In the meantime, heat the oven to 180 ° C.
Now place the puff pastry on a baking sheet lined with baking paper and distribute half of the onion mushroom mixture in the middle. Now put the loin on top and distribute the rest of the filling on top. Now carefully fold the puff pastry in and press it down on the sides. Spread the briefly whipped egg yolk evenly on the puff pastry with a brush and bake for about 30 minutes until golden.