Devils Food Cake & Frosting

Our answer

For the dark chocolate used in Nigella's recipes it is important to check the cocoa content (this should be stated on the packaging) - Nigella uses a chocolate with a minimum of 70% cocoa solids. Chocolates with a lower content will tend to have more sugar and other fats and less depth of flavour. There are a few brands that do chocolate of this quality, try Green and Black's or Lindt. For the US good quality bittersweet chocolate has minimum cocoa solids of 62% and Ghirardelli is a good brand. The European brands mentioned above are also available in some gourmet stores.

Unfortunately it is not possible to convert this cake to white chocolate. This is because white chocolate is made up of cocoa and other fats, sugar and vanilla and doesn't contain any cocoa solids so will cook and set in a very different manner to the dark chocolate. We have not seen a white cocoa powder.

If the chocolate frosting has gone grainy it is most likely that it has been overheated, causing the chocolate to "seize". It may have been that the water and butter mixture was boiling when the chocolate was added, it should be only just bubbling and if in doubt let it cool for a moment before adding the chocolate.