Heat the oven to 180C/160C fan/gas 4. Butter two 20cm round springform cake tins and line with baking parchment. Tip the butter, chocolate and sugar into a pan set over a low heat, stirring until fully melted together. Remove from the heat and leave to cool slightly, then add the eggs, one at a time, whisking well between each addition. Fold in the flour, cocoa, baking powder, bicarb, salt and spices. If the batter is too thick, you can loosen it with up to 3 tbsp milk, gradually adding it until the batter drops off the spoon with ease, but isn’t runny. Divide the batter equally between the prepared tins and bake for 25-30 mins until risen and a skewer inserted into the middle comes out clean. Leave to cool in the tins for 5 mins, then turn out onto a wire rack to cool completely.

For the buttercream, beat the butter with an electric whisk until very soft. Add the icing sugar, a spoonful at a time, whisking well between each addition, until you have a light, fluffy buttercream. Beat in the vanilla.

Put one of the sponges on a cake plate or stand, and spread a thick layer of buttercream on top. Sandwich with the other sponge and repeat with more buttercream. Spread the rest of the buttercream over the sides of the cake, scraping them slightly to create a ‘naked’ effect.

For the decoration, combine the ginger, cinnamon and nutmeg, then tip into a small sieve. Dust over the top of the cake, or use two strips of baking parchment to make a stripe template and dust a neat stripe on the surface. Cut into slices to serve. Will keep chilled for up to three days.