In a large bowl, beat the softened butter, sugar, vanilla sugar, and salt until light and fluffy.
Add the eggs one at a time, continuing to beat.
Pour in the milk and beat again.
Mix the flour and baking powder, then gradually add to the mixture.
Transfer 1/3 of the dough into a separate bowl and mix it with Nutella until smooth chocolate dough is formed.
Grease a 22 cm cake mold with butter. Pour in half of the white dough, then add all the chocolate dough. Finally, pour in the remaining white dough and smooth the surface.
Bake in a preheated oven at 170°C for 50-60 minutes.
Remove from the oven and let the cake cool completely.
Topping Preparation
Mix Nutella and milk, then slightly warm until a soft mixture forms.
Spread the mixture over the top of the cake.
Decorate with grated chocolate or as desired.
The result is an incredibly delicious, moist, and chocolatey treat, perfect to enjoy with tea or coffee.