How to cook
Sift the flour along with the dry yeast and make a well in it. Pour in the warmed milk, salt, sugar and olive oil and knead a smooth dough. Put the dough in a bowl with 2 tablespoons oil, cover with foil and leave it to rise until doubled in volume.
Roll out the risen dough to a sheet about 1/4 (5 mm) thick. For the filling, beat the egg with a pinch of salt using a fork and mash the feta cheese in it.
Distribute the filling along the sheet and put cubes of the butter here and there. Roll up the sheet, stretch it out into a wick, then cut out pieces about 3/4″ (2 cm) thick (you're going to get about 16 of them).
Arrange them in an oven dish (12″ (30 cm) wide) that you've smeared with the pork lard and leave them to rise one more time.
Make the topping by combining the beaten egg with a little salt, softened butter, 2 tablespoons flour and stir well with one small cup of milk.
Distribute this mixture onto each bun and put them to bake in a preheated 392°F (200° C) oven until reddened.