Stir the butter until foamy, then add all the other dough ingredients, stirring in between. The dough should be soft but not sticky. If necessary, add a little more flour. Knead the dough and place it in a covered bowl in the fridge for an hour.
After cooling, roll out the dough on a floured surface to the desired thickness (approx. 3 mm). Then cut out biscuits with a cookie cutter, place them on a baking sheet lined with baking paper and bake for about 10 minutes at 175 degrees (150 degrees convection). Then let it cool down, as the biscuits only harden when they cool down.
For the filling, stir all the ingredients together until creamy. Then put a dollop of cream on each cookie, which works very well with a simple teaspoon. Place a second biscuit on top of the cream, press down a little and let it set.