Dark and Sumptuous Chocolate Cake Icing

Our answer

The icing for Nigella's Dark And Sumptuous Chocolate Cake (from Simply Nigella and on the Nigella website) is a type of ganache. The icing ingredients, except for the chocolate, are heated to boiling point to dissolve the sugar, cocoa and espresso powders. Once this mixture has reached boiling point the heat should be turned off before the chocolate is added. Chocolate is sensitive to heat and we suspect that the liquid mixture may have been slightly too hot when the chocolate was added, causing the chocolate to either seize, or the ganache to split.

The heat should be turned off as soon as the liquid in the saucepan comes to the boil. If the mixture is allowed to boil at a full rolling boil then it may be too hot when the chocolate is added. If the mixture does boil fully in the pan then let it cool for a couple of minutes before adding the chocolate. If the mixture is very grainy then the chocolate has seized. Sometimes this can be corrected by stirring in a tablespoonful of a flavourless vegetable oil. If the icing is smooth but some oil has split out then this can often be corrected by beating the mixture vigourously, preferably with a hand mixer. However the icing may have a slightly dull look to it once it sets.