Cream soft fat, salt, sugar and vanilla sugar with the whisk of the hand mixer. Stir in the eggs one after the other. Mix flour and baking powder. Mix with 100 ml mineral water alternately into the sugar-egg mixture. Grease the fat pan of the oven and smooth down the dough. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 20 minutes. Leave to cool on a grid.
In the meantime, roughly chop the whole milk couverture. Heat the cream (do not boil!), stir in the chocolate coating and chill for at least 3 hours. Whip the mixture with the whisk of the hand mixer and spread on the baking sheet cake. Chill for about 30 minutes. In the meantime, roughly chop the white chocolate coating and melt over a water bath. Use a teaspoon of cow stains to spread on the cake. Allow to set and cut into 18 pieces