Leave the yoghurt out of the fridge until it reaches room temperature. Dissolve the yeast and the sugar in a little tepid water and set it aside to rise, covered. Sift the flour in a bowl and make a well in the middle.
Add the yeast, the yoghurt, the salt and the oil.
Knead and then set the dough aside in a warm place
Until it doubles.
Then, divide it into 4 balls which you press by hand into a round, thick filo sheet.
Distribute the feta cheese to the 4 filo sheets
And fold the pies in the middle. Press the edges well to seal.
Spread them out in a baking tray brushed with oil leaving a gap between them and set them aside for about 20 minutes. Brush them on top with the egg yolk and bake in a moderate preheated oven, until golden brown.
