Heat the oven to 200C/180C fan/gas 6. Oil two deep 20cm cake tins and line with baking parchment. Whisk the oil, eggs, buttermilk and cooled coffee together in a medium bowl until combined. In a separate large bowl, whisk together the flour, bicarb, baking powder, both the sugars and a pinch of salt, breaking up any lumps of sugar. Slowly drizzle the wet ingredients into the dry, whisking until smooth. Divide the batter between the two tins and bake for 20-25 mins, or until a skewer inserted into the middles comes out clean. Leave to cool in the tins for 10 mins, then invert onto a wire rack to cool completely.

Meanwhile, make the mascarpone icing. Beat the double cream, mascarpone, icing sugar, cocoa powder and Baileys together in a stand mixer or using an electric whisk until the mixture is thick, creamy and holds its shape.

When the cakes have cooled, spread a small dollop of icing in the middle of a cake plate or stand and put one sponge on top. Spread half the remaining icing over the top, then sandwich with the second sponge, making sure the flat side is facing up. Spread over the rest of the icing, swirling it with a palette knife. Decorate with chocolate shavings or chocolate-covered coffee beans, if you like. Will keep chilled for up to three days.