Smear the bottom of a tray (I used round one 12 1/2″ (32 cm) in diameter) with oil, although you can use butter or margarine if you prefer. Arrange the bread slices (I managed to fit 6), fill the gaps with crumbled bits. Smear with oil (or melted butter) on top using a brush.
Dissolve the baking soda in the yoghurt to become effervescent. Add the egg and stir well. Pour the mixture evenly over all the slices.
Crumble the feta cheese finely and sprinkle it over the slices.
Place the tray in a preheated 356°F (180 °C) oven and bake the phyllo pastry about 25 min. or until it gains a golden color. After you take it out of the oven, cover with a towel for about 10 min.
Cut it into 8 slices, like a pizza.
The result is an amazing snack and more. Enjoy!