100ml strong coffee (we made it with 2 tbsp coffee granules)
140g icing sugar, sifted
350g mascarpone or soft cheese
few chocolate-covered coffee beans
Heat oven to 180C/160C fan/gas 4. Grease a 20 x 30cm baking or roasting tin and line with baking parchment. To make the sponge batter, beat the butter, flour, sugar, baking powder, eggs, yogurt, vanilla, cocoa and half the coffee in a large bowl with an electric whisk until lump-free. Spoon into the tin, then bake for 25-30 mins until golden and risen and a skewer poked in comes out clean. Drizzle with some of the remaining coffee.
Cool in the tin while you stir the icing sugar into the mascarpone. Spread over the cooled cake, dust with a little cocoa and scatter with the coffee beans.