Heat the oven to 180C, fan oven 160C, gas mark 4.
Grease and line a 15cm wide, 8cm deep heart-shaped tin with baking parchment.
Put the beetroot and 2 tablespoon of the conserve in a blender and blitz for a few seconds to puree.
Put 100g of the chocolate and 100g of the butter into a large heatproof bowl and set over a saucepan of gently simmering water for 10 minutes to melt.
Meanwhile, sift together 70g of the flour, the baking powder and 5 teaspoon of the cocoa.
Stir the melted chocolate and butter together until smooth.
Now beat in the egg yolks until smooth.
Fold in the beetroot puree.
Whisk the egg whites until stiff then gradually whisk in 85g of the sugar until the egg whites are stiff and shiny.
Fold into the beetroot mixture.
Now sift the dry ingredients again into the bowl and fold in quickly using a large metal spoon.
Spoon the mixture into the prepared tin, turn the oven down to 160C, fan oven 140C, gas mark 3. and put in the oven for 45mins to 1hr.
A skewer pushed into the centre should come out clean.
Leave to cool in the tin before turning out.
Meanwhile, make the chocolate crumbs.
Put the remaining 55g of plain flour, 1 teaspoon cocoa, 25g caster sugar and 25g of butter into a small bowl and rub together until crumbly.
Spread on a foil-lined baking sheet and put into the oven for 15-20 minutes until lightly baked. Cool.
Finely grate the remaining 25g chocolate into the cold crumbs and add the hazelnuts.
Turn the cake bottom up and spread with the remaining conserve.
Spoon over the chocolate crumbs and pat down well into the conserve.
Put a heart of fresh raspberries on top and dust with icing sugar before serving.