Prepare a large tray, smear it well with oil and arrange the bread slices.
Fill the empty spaces with pieces from the remaining slices.
Turn the oven on to 392°F (200 °C).
In a suitable container, beat the eggs, add the yoghurt, feta cheese, water, salt and oil to them.
Stir lightly and pour this evenly over the arranged bread slices.
Bake the phyllo pastry for 20 min. at the same temperature.