How to cook
Put the yoghurt and baking soda in a bowl, leave them until the baking soda bubbles. Add the egg and beat, then add the chopped olives + crumbled feta cheese.
Add enough flour to get a thick, sticky dough. Use a spoon to fill muffin forms with the dough.
Put a piece of butter and cheese on top of each doughy pile. Bake at 392°F (200 °C) until ready.