Preheat your oven to 250/300°C, and put your fire stone directly in the oven if you have one.
Prepare the dough: mix the flour, salt, then add the water and oil. Knead until you get a nice ball of non-sticky dough. Add flour if necessary, and adjust (very slightly) the amount of water if necessary. Let sit while you prepare the filling.
Slice the onions and mushrooms.
In a frying pan, fry the lardons. Once cooked, deglaze with the white wine. Then add the finely minced onions, leave to cook for a few minutes, and then add the mushrooms and set aside.
Mix the sour cream and the whipped cottage cheese. Add as much grounded nutmeg as you like and pepper.
Roll out your dough on a floured work surface, until you get a fine, rectangular dough. Brush with your cream / cottage cheese mixture, add the bacon / onion / mushroom mixture, and sprinkle with finely chopped fresh parsley.
Put in a very hot oven, let it bake between 10 to 15 min (check that it does not burn!).