Dissolve yeast in warm water, add sugar and allow to rise until "cap". In a bowl sift the flour, add salt, pour the yeast and butter. Begin to knead the dough, gradually adding water. You should get a smooth dough. Spread the dough on the table, covered with flour, and knead the dough for 10 minutes.

Coat the dough lightly in flour, place in bowl, cover with a towel and let the dough time for about an hour. Then again abenaim, make a ball, wrap in clingfilm and put into the fridge for at least 2 hours.

During this time, prepare the filling. Boil the potatoes, cool, peel and cut into circles with thickness of 0.5-0.7 mm. Mushrooms wash, cut and fry in vegetable oil with salt and pepper to your taste. I took to stuffing the mushroom caviar. Cut onion into chetvertfinalny. You can marinate it and use. Prepare the second dough for top of pie. In warm milk bred yeast, let them "earn". Add the remaining ingredients and leave in a warm place until increased two times. After a time, removed from the refrigerator dough, roll out into a circle.

Put into the form, lightly greased and moulded Skirtings. The first layer put potatoes (salt, pepper)

Fill the potatoes with the beaten egg. Arrange the onion on top.

Bow cover "blanket" of mushrooms.

Yeast roll out the dough, grease with lard and cut into thin strips (about 1 cm wide).

Lay these strips over the filling, giving it an "artistic mess". Grease with egg yolk and bake it in the oven for 25-30 minutes. The temperature of 200*. Adjust time for your oven.