Spray and line a 20 cm / 8 in cake tin. You will need a collar of double thickness baking paper or an acetate collar. Oven 170C / 340 F
Make a strong esspresso coffee (125ml)
Mix the first 9 ingredients. Flour, sugar, cocoa, baking powder, soda, salt, cinnamon, nutmeg and allspice in a large bowl.
In a separate bowl mix the oil, buttermilk, coffee, vanilla and egg together well.
Pour the wet ingredients into the dry ingredients and mix until well combined, shiny and smooth.
Pour the cake into the cake tin and put it into the oven. Bake until a skewer inserted into the centre comes out clean. Approximately 35 to 40 minutes
Cool on a rack and chill well before trimming off the uneven top edge to leave a nice flat round cake. Slice the cake into two thin layers.