How to make
First, prepare the filling. Beat 2 eggs and 1 egg white in a bowl. Add the crumbled feta cheese and the yoghurt in which you've stirred the baking powder.
Stir everything to mix well. Melt the butter and mix it with the oil.
Take a phyllo pastry sheet, smear it lightly with the oil using a brush and place a 2nd sheet on top. Grease it tool. Fold the sheets in 2 lengthwise in order to form a long, narrow strip.
Smear it lightly with oil again. Scoop from the filling with a spoon and distribute it over the resulting strip.
To form the phyllo pastries, grab 1 of the lower ends and fold it diagonally along the strip. Take the other angle and fold along the strip's length.
Repeat this process until you've folded up the entire strip into a packet. If there's a small part of the strip left over at the end, tuck it into the resulting pocket. Arrange the phyllo pastries in a tray covered with baking paper.
Smear them with the remaining beaten yolk and put to bake in a 370°F (190 °C) oven until they gain a nice golden crisp.
After you take them out of the oven, sprinkle lightly with water and cover briefly with a clean cotton towel.