Start by making the chocolate icing. Put the chocolate pieces and double cream in a heatproof bowl. Boil about 4cm of water in a pan (big enough to easily fit the heatproof bowl). Once the water is boiling, turn the heat off. Place the bowl with the chocolate and cream in the boiled water and stir the chocolate around until it begins to melt.

Once the chocolate has completely melted remove the bowl from the pan and allow it to cool down a little (about 5 minutes). Place the bowl in a fridge for about 1 hour, stirring occassionally.

Preheat oven to 180C/Gas Mark 4.

Prepare 2 x round 20cm/8 inch baking tins by greasing them, and lining with greaseproof paper.

Sift the flour, cocoa powder and baking powder into a large mixing bowl. Add the sugar, beaten eggs, butter/margarine and milk. Mix everything together until it is well combined.

Transfer the chocolate batter mixture to the previously greased baking tins. Divide the mixture evenly between the 2 tins and smooth them out until they are level.

Place both tins in the (preheated oven) and bake for approx 25 minutes, until the cakes are springy to the touch.

Remove both the cakes from the oven and leave them to cool for 10 minutes before carefully removing them from the tin. Leave them to cool some more on a wire rack.

Retrieve the chocolate icing from the fridge and leave it out at room temperature for about 5 minutes to soften up a little before spreading some of it across one of the cakes.

Place the other cake on top so that the chocolate icing is sandwiched in between. Spread the remaining chocolate icing across the top of the cake. Optionally decorate with chocolate buttons or the topping of your choice.