Preheat the oven to 200C/400F/Gas Mark 6.

Brush a 25 x30cm baking tray or swiss roll pan with a little oil or melted butter. Line the base and sides with some parchment paper.

Melt the chocolate in a heatproof bowl over a saucepan half filled with water (ensuring the water does not touch the base of the bowl). Stir until smooth.

In a separate bowl beat the eggs and sugar until light and creamy. Stir the water and bicarbonate soda into the melted chocolate. Sift the flour into the eggs and stir in the ground almonds. Pour in the chocolate mixture and stir to combine. Pour the batter into the lined baking tray and bake for 10 minutes.

Place a layer of parchment paper larger than the baking tray onto a flat surface. Invert the cake onto the parchment paper and trim any crispy edges. Starting with the long side closest to you, and using the paper to help, roll up the cake. Place seam side down on a wire rack to cool.

Meanwhile, to prepare the filling beat the mascarpone cream, cream and chocolate spread into a bowl and beat until smooth. Unroll the cake and spread with the cream mixture then roll up again.

Prepare the butter icing by placing the ingredients in a bowl and whisking with an electric whisk until smooth. It should be a lovely light brown colour. Using a palate knife or piping bag, spread the butter icing over the cake and top with some chocolate shavings.

Place in the fridge until required.