1. Prepare the dough: combine flour and salt in a large bowl. Cut a piece weighing 10 g from butter, cut the rest of the butter into small cubes. Add the cubes of cold butter to the flour and grind the mixture with a knife, hands or food processor until crumbs are obtained.
Separately mix ice water and yolk. Pour the mixture of yolk and water into the flour, quickly knead the dough and collect in a bowl. Form a flat cake (so it will be easier to roll out the dough later), wrap it with cling film and put it in the refrigerator for at least 1 hour.
2. Turn on the oven to warm up to 180 degrees.
Take the dough out of the refrigerator and roll it out onto a 3-5 mm thick circle on the work surface sprinkled with flour.
Cover the bottom of the split baking dish with parchment paper and carefully transfer the dough into the mold, forming the sides. Make frequent pricks with a fork on the test (so it will not swell during baking).
Cover the bottom with baking paper or foil and lay out the load (dry beans or peas, special ceramic balls for baking). Bake for 15 minutes. Remove the form from the oven, remove the paper with the load and cool.
3. Prepare the filling for the quiche and pour: for this, grate the cheese on a coarse grater (it is better to take it with a pronounced taste so that the taste of the pie does not seem to be “flat” and “too boring” in the end).
Cut the mushrooms into thin slices (if you cook the quiche in the winter, if possible, take the royal mushrooms - they are more fragrant). Melt the butter over medium heat in a pan and fry the mushrooms until golden brown.
Separately mix eggs, sour cream, grated cheese, dried thyme or fresh leaves (you need 3-4 sprigs) and nutmeg. Salt to taste.
4. Put half the fried mushrooms on the basis of the baked dough and pour the egg and cheese fill on top. Distribute the remaining mushrooms according to the filling.
Bake 40-50 minutes until cooked in a preheated oven. Kish is ready if the middle of the pie is seized, and the top is browned.
5. Quiche with mushrooms and cheese is ready. It can be served both warm and cold. Bon Appetit!