For the cake base, first knead a shortcrust dough from the specified dough ingredients (preferably in a food processor) and let it rest in a cool place for half an hour.
After the cooling time, roll out the dough to a thickness of approx. 3 mm. Place desired number templates of the same size. Cut the dough along the templates with a knife: When doing so, cut out each required number twice (!) from the dough: For example, for the photo, two threes and two zeros were cut out. Place the numbers on a baking tray covered with baking paper. Prick several times with a fork and bake at 200 °C for about 12 minutes. Let the pastry sheets cool completely.
Prepare a pudding from pudding powder and milk according to package instructions (but without added sugar) and let cool completely, stirring well every now and then.
For the cream, cream butter with powdered sugar until very fluffy. Stir in the chocolate and the cold pudding by the spoonful. Then pour into a piping bag and pipe dots on top of the pastry sheets, place the next sheet on top and pipe another layer of dots.
Decorate the top of the cake with sugar decorations as desired.