Beat the eggs in a large bowl, add the yoghurt with baking soda extinguished in it.
Next add the oil, feta cheese and carbonated water. If you feel it necessary, add a little salt as well.
Roll up all the Phyllo pastry sheets together and cut into round slices 1/2″ (1 cm) thick. Unroll them, so there's no stuck together sheets, add them to the egg-yoghurt mixture.
Stir well and pour mixture into oiled muffin forms to fill them.
Bake in preheated 374°F (190 °C) oven to a golden crisp.
After baking leave the muffins for 10 min. in the forms and only then take them out.
When prepared this way they'll have a crunchy crust outside and soft inside, plus are easy to serve to guests.
They're tasty both warm and cold, served with ayran, millet ale, feta cheese, jam or pestil.