Coarsely chop 100 g chocolate and melt over a warm water bath. Cut beetroot into large pieces, puree in a tall container.
Cream 150 g butter, sugar, salt and vanilla sugar with the whisk of the hand mixer. Stir in the eggs one after the other. Stir in liquid chocolate. Mix flour and baking powder and stir in alternately with the puree.
Pour into a greased, floured box form (11 x 30 cm; 1.75 litre capacity) and bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 50 minutes.
Remove and let it cool down.
Carefully remove the cake from the mould. Grate 50 g of chocolate with a peeler into small rolls. Break 150 g chocolate into pieces and put them into a pot with 125 g cream. Melt at low heat while stirring.
Place the cake on a grid, cover with icing. Sort the raspberries. Decorate cake with raspberries and chocolate rolls.