In a bowl, beat the eggs, add the yoghurt with baking powder, crumble the feta cheese, add the oil. Stir everything. Crumble the bread into pieces along with its crust.
Add it to the bowl, while stirring once again, so that all of the pieces get covered with the mixture.
Smear an oven dish with a little butter, pour the contents of the bowl in it, break up the rest of the butter on top and put it in a preheated 356°F (180 °C) for 40 min. until golden.