Add the soft butter and the sugar to a bowl and mix the whole content to a smooth paste.
Slit open your vanilla bean and scratch out with a butter knife the black seeds in the vanilla bean. Add the vanilla seeds to the mixing bowl and store the left over vanilla bean for another recipe, another time (we don't waste expensive ingredients!). Add the flour and water to the mixing bowl too and mix the whole content to a smooth dough. The dough shouldn't stick but should be able to form a whole dough without breaking apart. Wrap the dough into clean wrap and place into the fridge. Let cool for 1 hour.
Roll out the dough with enough flour so that it doesn't stick. The dough should be about 3 mm thick. Cut out your biscuits with a cookie cutter and place on a baking parchment with sheet. Finnish up the whole dough by rolling out and cutting out the biscuits and bake the cookies with 160 Celsius for 15 minutes.
Let cool your cookies and melt your chocolate in a bain marie (pot with water and another pot in the water containing the chocolate) so that the chocolate doesn't burn. Pour the chocolate into the mold and let cool for 20 minutes. Once cooled add some of the molten chocolate onto the biscuit side to glue it on and stick the chocolate molding onto the biscuit.
Store the biscuits in a cool and dry place.
Notes
You can use Dark Chocolate and/or White Chocolate and/or Milk Chocolate