Grease and base line two 18cm (7 inch) sandwich tons. Preheat the oven to Gas Mark 4/180'c/350'F.

Place them margarine and sugar in a mixing bowl. Sift in the flour, cocoa and baking powder. Add the eggs and vanilla extract. Whisk the ingredients together for 2 minutes only, scraping the mixture down halfway through to ensure that all the ingredients are evenly combined.

Divide the batter between the prepared tins. Smooth the surface and make a slight dent in the centre of each. Bake for about 25 minutes until the surface is springy to the touch.

Remove from the oven and leave in the tins for 5 minutes before running a knife around the edges and turning the cakes out onto a wire rack to cool.

Once cooled, spread one of the sponges with conserve. Place the other on top and press down lightly.

For the icing, place all the ingredients in a bowl over a pan of hot water. Leave them to melt, stirring occasionally. Once melted, remove from the heat and stir until smooth then allow to cool to a spreadable consistency. Using a palette knife, smooth the icing over the surface of the cake and decorate with chocolate curls or a crumbled Flake. Leave the icing to set before serving.