Mix butter with powdered sugar until creamy consistency.
In a separate bowl mix all dry ingredients and stir them well.
Mix together dry ingredients with butter, add water to it and knead the dough, then let the dough rest for 30 min.
Roll out the dough (tall 1 cm - 1,3 cm) and cut out cakes (6 cm diameter) and place them on a baking tray covered with a parchment paper. Repeat until all of the dough is used. Bake at 180 degrees Celsius for 12-13 min. Take cookies out and let them cool down.
Make filling: mix butter with powdered sugar until creamy consistency, then add melted chocolate to it. Mix all well, put in a piping bag with decorative noozles and fill half of the biscuits, cover them with the second halves and set aside.
Glazing: in microwave melt together chocolate and whipped cream on 30 second intervals, then continue with 5-10 sec. intervals, stirring well between breaks (you can do this step over the stove in a pot making sure that it doesn't burn!). Use the glaze to cover the top of cookies by dipping them into the glaze, then let them rest. Store in a cold place for up to 6 days.