Mash the feta cheese and mix it with the eggs and yoghurt with the baking soda extinguished in it. Add the salt, sugar and flour.
Take 2 phyllo pastry sheets at a time and sprinkle them with oil. At one end, put filling along the width and roll it up into a not-too-tight roll.
Put it in a buttered tray and arrange the rest of the rolls in a circle. Pour the rest of the filling on top. If there's not enough of it, add 1 egg.
Distribute small pieces of butter over the phyllo pastry and put it to bake in a preheated 356°F (180 °C) oven.