How to cook
For the filling:
In a bowl, pour the sifted flour with the baking powder, add the milk, beaten egg whites, oil, melted butter and salt. Knead a medium soft dough that doesn't stick to the hands and leave it in the fridge for 20 min.
After taking it out, tear it into balls the size of a walnut, arrange them in a buttered oven dish some distance apart from one another, so they don't stick, and leave them to sit for 10 min.
Roll out the balls onto an oiled counter into sheets the size of a tea cup saucer. Put filling in their middle and cover it, use a fork to pinch the edges of the feta cheese bun closed.
Arrange the feta cheese buns in an oven dish covered with baking paper and smear them with the beaten yolks, to which you've added oil. Sprinkle with sesame seeds.
Bake in a preheated 392°F (200 °C) oven for 20-30 min. until reddened.