Cream fat, sugar, salt and vanilla sugar with the whisk of the hand mixer until the sugar is dissolved. Stir in the eggs one after the other. Mix flour, cocoa and baking powder and stir in.
Roll the Milky Way dice. Carefully knead Milky Ways and cornflakes into the dough. Using a teaspoon, place 10 piles of dough on each of 3 baking trays lined with baking paper and flatten slightly to form cookies (6 cm Ø each).
Bake the trays one after the other in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 10-12 minutes. Remove cookies from the oven, place them on a cake rack and let them cool down.
Meanwhile, chop the chocolate coating roughly and melt it in a hot water bath. Pour the couverture into a freezer bag, cut off a small corner and spray strips onto the cookies.