1. Heat the oven to 180C/160C fan/gas 4. Line three 30cm sandwich cake tins with baking parchment. In a pan over a gentle heat, slowly melt the butter, Dr. Oetker 54% Dark Chocolate, sugar and 180ml cold water. Once melted, leave to cool.
2. Add the eggs, oil, Dr. Oetker Vanilla Extract and soured cream to the cooled chocolate mixture and stir well. Sift the self-raising flour, plain flour, Dr. Oetker Fine Dark Cocoa Powder and Dr. Oetker Bicarbonate of Soda into a large mixing bowl, then make a well in the centre. Pour the chocolate mixture into the well, then mix until thoroughly combined. Divide the batter evenly between the lined tins and bake for 30 mins, or until a skewer inserted into the centre of the cakes comes out clean. Set aside and leave the cake to cool in the tin.
3. When the cake has cooled, place one of the sponges onto a serving plate. Spoon the Dr. Oetker Rich Chocolate Buttercream Style Icing into a large piping bag that’s fitted with a large open star nozzle. Pipe buttercream swirls onto the sponge, then add a dollop in the middle of the cake. Put the other sponge on top (the weight will spread out the filling) and repeat with the next layer. Smooth the icing on top of the cake with a pallet knife, then finish by piping buttercream swirls around the top edge of the cake, then add Dr. Oetker Giant Chocolate Stars and sprinkle over Dr. Oetker Chocolatey Sprinkle Mix. Finish with candles and serve. This cake will keep in an airtight container for three days.