How to make
Dissolve the yeast in some warm water with a pinch of sugar. Sift the flour and in the middle, make a well, add the yeast and all the other products, excluding the butter. Knead a smooth dough, adding flour until you get a nice and firm dough. Let it rise.
Knead the risen dough and divide it into 5 equal balls. Roll out each one into a large rectangle and stack them on top of one another, sprinkling with plenty of butter and crumbled feta cheese. Roll out the stacked sheets carefully once again and cut them into vertical strips. Stretch out each strip and twist into a knot with your hands.
Arrange the resulting knots in a well-buttered tray and allow to rise again. Then coat with the egg yolk that you've beaten with a little water, sprinkle with sesame or poppy seeds and bake in a moderately heated oven.