Flour, sugar, vanilla sugar, and cocoa are mixed in a bowl – I typically use a hand mixer.
The margarine is crumbled into the mixture along with the egg and water.
Mix everything well together.
Pour the mass onto baking paper.
Roll the dough into logs in the desired cookie size.
Chill for a few hours, making it easier to slice.
Cut the dough into thin slices, about 2 mm thick.
Bake at 200 degrees Celsius (392 degrees Fahrenheit) for 9 minutes.