Mix butter, eggs, vanilla sugar, sugar, natural yogurt, flour and baking powder to form a light and fluffy batter.
Add the peeled apples to the batter and gently stir them in.
Line a springform pan (approx. 24cm) with baking paper and pour in the batter.
Top the dough with 2-3 tablespoons of sugar and cinnamon.
Bake the cake at 180 degrees Celsius (350 degrees Fahrenheit) using a convection oven for approximately 40-45 minutes until golden brown.
Do the toothpick test. If it's not cooked through yet, cover and bake for another 10 minutes.
