How to make
Beat the eggs with the sugar very well.
Then sift the flour, baking powder and cocoa with a sieve.
Separately, beat the butter and yoghurt.
Mix all of the liquid ingredients first, then slowly start adding the flour, baking powder and cocoa mixture, finally add the chocolate.
Pour it out into muffin cups and bake in a preheated 330°F (165 °C) oven about 20-25 min.