When I make the Dark And Sumptuous Chocolate Cake I let the finely chopped chocolate melt into the other ingredients and then whisk. It goes glossy for a second then suddenly turns grainy and dull instead of glossy and smooth. Am I over-whisking it?
The icing from Nigella's Dark And Sumptuous Chocolate Cake (from SIMPLY NIGELLA) is a type of ganache made with dark chocolate, coconut butter, dark brown sugar, cocoa powder and water. All of the ingredients except for the chocolte are melted together in a saucepan and then brought up just to boiling point, before the heat is turned off and the chocolate is added and left to melt.
If the mixture is turning grainy as it is mixed it is most likely that the liquid was a bit too hot when the chocolate was added and the heat has caused the chocolate to seize. Turn the heat off underneath the pan as soon as the mixture starts to bubble around the edges of the pan and add the chocolate once the bubbles have subsided. If the melted mixture gets to a full boil then let the pan cool for a couple of minutes before adding the chocolate.