I have given a generous amount of icing to fill and ice this cake, as it should be sheer luxury and a complete indulgence! The icing is very easy to make, but take care not to overheat it or it will lose its shine. For the same reason, don’t store the cake in the fridge – a cool place is fine.
Cake tins needed: 2 loose-based 20cm (8in) sandwich tins, 4cm (1½in) deep
275g (10oz) plain flour
3 tbsp cocoa powder
1½ level tsp bicarbonate of soda
1½ level tsp baking powder
215g (7½oz) caster sugar
3 tbsp golden syrup
3 large eggs, beaten
225ml (8fl oz) sunflower oil
225ml (8fl oz) milk
for the icing
450g (1lb) plain chocolate (39 per cent cocoa solids), broken into pieces
200g (7oz) unsalted butter
for the chocolate waves
about 50g (2oz) each white and plain chocolate (39 per cent cocoa solids)
Step one Preheat the oven to 160°C/Fan 140°C/gas 3. Grease both the tins and line the bases with non-stick baking parchment.
Step two Sift the flour, cocoa powder, bicarbonate of soda and baking powder into a large bowl. Add the sugar and mix well.
Step three Make a well in the centre of the dry ingredients and add the golden syrup, eggs, oil and milk. Beat well, using a wooden spoon, until smooth and then pour into the tins.
Step four Bake for about 35 minutes, until the cakes are well risen and spring back when pressed lightly with the fingertips. Turn out onto a wire rack, remove the lining paper and leave to cool completely. Cut each cake in half horizontally.
Step five To make the icing, put the chocolate into a bowl placed over a pan of hot water. The water in the pan must not touch the bowl or the chocolate may overheat. Place the pan over a low heat until the chocolate has melted, stirring occasionally, then add the butter and stir until the butter has melted.
Step six Put the bottom half of one cake on a wire rack and place a baking sheet underneath to catch the drips. Spoon a little of the icing onto the cake and spread it evenly to the sides. Repeat with the remaining cake layers, then pour the remaining icing over the top of the cake and smooth it evenly over the top and sides of the cake. Leave to set.
Step seven To make the chocolate waves, melt the chocolates in separate small bowls over a pan of hot water. Spread the chocolate onto four strips of foil about 4cm (1½in) wide and 35cm (14in) long. Lay the strips carefully over 2 tins, placed on their sides on a baking sheet, to give a wavy shape. Allow to set in the fridge, then carefully peel off the foil and use.