Chocolate Icing

Our answer

When you melt chocolate at home it tends to become dull when it sets. The reason the chocolate doesn't remain shiny is that the melted cocoa butter forms different size crystals as the chocolate cools, and this makes the chocolate look dull. Tempering is a process used for chocolate which makes it shiny and smooth and involves taking chocolate through 3 controlled temperature changes.

Tempering is not something we would really try at home, unless you have a very good digital (instant read) thermometer and the facilities to heat and cool chocolate fairly quickly to the correct temperatures. Also dark (bittersweet), milk and white chocolate all have to be taken to different temperature points. If however you want a dark, shiny icing on your cake then we would suggest using a ganache icing. Ganache is a mixture of cream and dark chocolate and once poured over, or spread on, the cake and cooled it will form a fairly firm and shiny icing.

Nigella uses ganache icing in several cakes but we would suggest trying the icing on Nigella's Nutella Cake (from Domestic Goddess) which uses equal weights of chocolate and cream. For a layer cake you will likely need 250g (9 ounces) dark chcocolate and 250ml (1 cup) double cream (heavy cream) to cover the outside.