Halve 12 Oreos, placing the cream side up at the bottom of each muffin cup.

Whisk eggs and sugar until light and airy.

Mix flour, sugar, eggs, milk, butter, vanilla sugar, baking powder, and cocoa into the egg mixture until a smooth batter forms.

Crush the remaining Oreo cookies and fold them into the batter.

Distribute the batter in the muffin cups over the halved Oreo.

Bake your Oreo cupcakes for 15-20 minutes at 175 degrees Celsius (347 degrees Fahrenheit).

Let your cupcakes cool, and cut a hole in the center of each before decorating with frosting.

Whisk butter, powdered sugar, the crushed Oreos, and vanilla sugar together into a smooth frosting.

Fold in the cream cheese with a spatula.

Put your frosting in a piping bag with a large star nozzle and first fill the hole in your cooled cupcakes, then decorate the top.

Top with an Oreo cookie and serve.