In a large mixing bowl combine all dough ingredients and work with your hands, kneading until the smooth dough is formed.Wrap the dough in a transparent kitchen foil and put it in the fridge for 1 hour.Preheat oven to 190 C (375 F). Prepare the large baking tray and line it with parchment paper.Roll the dough in a long shape, cut small slices and form the cookies. You can also just take smaller pieces of dough from the dough ball and form long shaped cookies by rolling them with your hands.Place the cookies on a tray and bake them for 10-12 minutes until just slightly golden.They will be soft when you remove them from the oven but don't worry, they will harden as they cool down.While the cookies are cooling down, prepare the chocolate for the topping by melting it over the steam (bain marie) of boiling water.Dip each cookie into the melted chocolate and sprinkle them with colorful sprinkles for decoration.Leave the cookies on the tray until the chocolate topping dries and than store them in the metal box / airtight container.