Pre-heat the oven to 180 C/Gas Mark 4. Grease and line a 9 inch loose bottomed cake tin.
Break the chocolate into pieces and put in a food processor. Blitz until crumbed but not totally powdered - some larger pieces will give the cake a great texture.
Add the beetroot and blend together. Then add the remaining ingredients to the processor and whizz until well mixed. Pour into the prepared cake tin and lightly level out the surface.
Bake in the preheated oven for 45-50 minutes or until a skewer inserted into the centre comes out clean. The surface of the cake may have cracked a little. Allow the cake to cool for a few minutes in the tin before removing to a cooling rack.
Dust lightly with icing sugar and serve in wedges. For dessert, this cake is great with a little creme fraiche on the side.