Peel apples and cut into cubes. Grease a muffin tin with butter or line it with paper liners.
Mix the flour with the baking powder separately.
Mix the eggs with the yogurt, sugar and oil well. Now add the apple cubes and mix well. Then briefly fold in the flour mixture (I usually only work with a whisk) and then immediately pour into the muffin tins. Finally, press a piece of chocolate into each muffin tin.
Bake the whole thing at 180 ° C in a preheated oven for 15-20 minutes.