For the dough, roughly chop 100 g of chocolate and melt over a warm water bath. Leave to cool. Whip the fat, vanilla sugar, sugar and salt until creamy with the whisk of the hand mixer.
Stir in the eggs one by one. Mix flour, baking powder and cocoa, add and stir in. Stir in 50 ml milk. Let the chocolate shrink while stirring.
Place the dough on a well greased baking tray (35 x 40 cm), smooth it down and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 15-18 minutes. Remove from the oven, place on a cake rack and let cool.
Roughly chop the rest of the chocolate and melt over a warm water bath. Slowly let 100 ml milk run in while stirring continuously. Let it cool down, stirring several times. Whip cream in 2 portions until stiff and fold into the liquid chocolate in portions.
Cover and chill for about 40 minutes.
Cut the cake into 30 squares. Spread half of the squares loosely with 2/3 of the mousse. Spread the remaining squares with the remaining mousse. Cut a circle in the middle of each square with a punched spout (wide side, approx. 3 cm Ø).
Use cake remains for other purposes (e.g. rum balls). Place squares on top of each other so that the ones with a hole are on top. Sprinkle with chocolate shavings and chill for about 1 1/2 hours.
Knead marzipan and icing sugar. Colour orange with food colouring. Form 15 carrots (approx. 3.5 cm long) from the mixture. Cut fruit gum strings into pieces of approx. 3 cm. Use a wooden skewer to prick the top end of the carrot as "green".
Draw a face on the carrots with a food pencil. Place the carrots in the hollows of the cake pieces and arrange them on a plate.