Preheat the oven to 160 C / and grease and line a 20cm round cake (at least 7 cm deep) or 2 x 18cm cake tins pan with baking paper.

Break the chocolate into pieces in a small pan and add the butter.

Dissolve the coffee with 125ml of cold water and then add to the butter and chocolate mixture and melt all together over gentle heat. Do not boil. Set aside to cool.

In a bowl sift the 2 flours and bicarb.

Using a small food processor, grind the raisins with the white sugar until it’s as fine as it will go. It may clump a bit but don’t worry. If your food processor bowl can accommodate all the sugar, then add the brown sugar as well.

Add the sugar mix, sugar and cocoa to the flour and mix until combined. Use your hands if necessary to break up any clumps of raisin sugar.

In a separate bowl beat the eggs until light and fluffy. Add the buttermilk and briefly beat it together.

Add the cooled chocolate mixture and the egg/buttermilk mix to the dry mix and fold it all together by hand.

Pour the mixture into the prepared cake tin (or two tins) and bake for 1 hour 25 minutes – 1 ½ hours. If you are using 2 x 18cm tins – the cakes should be baked in 1 hour. Check by piercing the cake with a small sharp knife or skewer. The cake is done if it should come out clean and should be springy to the touch. The top of the cake will be firm and may have a few cracks.

Allow the cake to cool in the tin, and when it's completely cool, remove it from the tin and peel off the paper.

Cut the cake into 2 or 3 horizontally (or the 18cm into 2 making a total of 4 layers for the cake) and ice the cake with the chocolate frosting

To make the frosting place all the ingredients in the bowl of a stand mixer and whisk until light and very fluffy. You can use a handheld electric beater for this too.