Heat the oven to 180C/160C fan/gas 4. Butter and line the base and sides of 2 x 20cm round cake tins. Tip the butter and chocolate into a heatproof bowl. Set the bowl above a saucepan filled with simmering water ensuring the bowl doesn’t touch the water. Stir regularly, until melted then remove from the heat. Alternatively, you can melt in the microwave in 20-second bursts, stirring regularly.

Sieve the cocoa powder and malted chocolate drink powder into a large bowl. Add the flour, sugar, bicarb and baking powder along with a large pinch of salt and whisk together. In a jug, whisk together the eggs, buttermilk, coffee and vanilla, then pour into the dry ingredients. Whisk well until smooth, then pour in the melted chocolate and mix to make a smooth batter. Divide between the tins and bake for 35-40 mins, until a skewer inserted into the middle comes out clean. Set aside on a wire rack to cool completely. Will keep in an airtight container for up to two days.

To make the icing, tip the chocolate into a heatproof bowl and set aside. Tip the malted drink powder, sugar, butter, and cream into a saucepan and set over a medium-low heat. Heat gently until the sugar and butter have melted, then pour this over the chocolate, whisking well. If the chocolate hasn’t melted, fill the saucepan with hot water from the kettle and set the bowl over the top, then whisk again. Using electric beaters, beat the mixture until thick and glossy, then add the mascarpone and continue to beat until well mixed. Set aside to cool to room temperature (it will thicken as it cools).

When ready to assemble, set one of the cakes on a cake stand or serving plate then spoon over some of the cooled icing, spreading out evenly over the cake. Sandwich with the other sponge, then layer over the remaining icing, thickly spreading over the top and sides of the cake. Scatter over some milk chocolate shavings, sprinkles and Maltesers® to decorate. Will keep covered for up to four days.