This is the outermost layer of the cake. The original recipe used gelatine to make its consistency slightly stretchy. This results in a smooth surface that doesn't crack when the cake is cut, but it means the cake isn't vegetarian. I experimented with vegetarian gelatine alternatives instead. We used a mixture of plain and milk chocolate in the coating sauce.

Original recipe

• 1 leaf gelatine

• 9 fl oz milk

• 100g / 3 1/2oz liquid glucose

• 300g chocolate (note: I still bought this from the baking section, not the confectionery aisle)

• 300g cooking chocolate

Instructions

• Soak the gelatine in a small amount of warm water and leave it to cool.

• Boil the milk and liquid glucose in a saucepan.

• Add the gelatine to the glucose mixture.

• Melt the chocolate and cooking chocolate in a bain marie.

• Mix everything together. Time this carefully so the glucose mixture is cool enough not to scald the chocolate, but has not solidified yet.

• Store the sauce in an airtight container overnight.

• When you are ready to use the sauce, warm it and pour it over the cake.

Modification for vegetarians

Replace the gelatine with 1/2 teaspoon of Supercook Vege Gel, mixed with 50 ml of water. The problem with this replacement is that it can make the sauce bobbly looking; however, a lot of work stirring it with a fork can improve this to some extent. It will look better again after being left overnight, and final smoothing on the cake can be done with a very long warmed palette knife.