A big party cake made from three layers of rich, moist mocha sponge, sandwiched and frosted with buttercream flavoured with Irish cream liqueur and coffee – then decorated with white chocolate ‘ice shards’ and ‘snowballs’.
To make the sponges: heat the oven to 180°C/160°C fan/350°F/Gas 4. Melt the butter and leave to cool. Sift the flour, cocoa powder, baking powder, bicarbonate of soda and salt into a large mixing bowl. Add the sugar and mix together. Make a well in the centre of the mixture.
Break the eggs into the milk and beat with a fork until thoroughly combined, then mix into the melted butter with the hot coffee. Pour into the well in the flour mixture and stir everything together with a wooden spoon. When smooth and thoroughly combined, pour the mixture into the 3 tins so they are equally filled.
Bake the sponges in the oven for about 25 minutes until each is well risen, starting to shrink away from the sides of the tin, and a skewer inserted into the centre of the sponge comes out clean. Run a knife around the inside of the tins to loosen the sponges, leave to firm up for 3 minutes then turn out onto a wire rack and leave to cool. At this point, the sponges can be kept overnight in an airtight container.
Meanwhile, make the buttercream: beat the butter with an electric hand whisk or stand mixer for about 3 minutes – or until very creamy and pale. Gradually beat in the sifted icing sugar on a slow speed, scraping down the sides of the bowl from time to time. When all the icing sugar has been incorporated, add the salt then beat on high speed for 3-4 minutes until the buttercream is very light and fluffy. Gradually beat in the Irish cream liqueur or cold coffee, then transfer ⅔ of the buttercream to another bowl and set aside for the frosting.
Once the sponges are cold, start to assemble the cake: place one sponge top-side down on a serving board or cake board. Sprinkle or brush with 1 tablespoon of the coffee liqueur (if using) then spread with half the buttercream left in the mixing bowl. Cover with another sponge (top-side down) and repeat. Top with the third sponge (top-side up), then sprinkle or brush with the last tablespoon of coffee liqueur (if using). Use about ⅓ of the reserved buttercream to thinly cover the top and sides of the sponge – this is the crumb-catcher coating. Chill until firm.
Meanwhile, make the chocolate shards: gently melt the chocolate in the microwave in 10-second bursts, or in a heatproof bowl placed over a pan of steaming hot (but not boiling) water – don't let the base of the bowl touch the water. Stir the chocolate until very smooth, then drop a tablespoon onto the acetate or baking paper and spread into a large shard shape. Add texture with a round-bladed knife or clean cake-decorating paintbrush/pastry brush, then sprinkle with a little of the lustre dust if using. Repeat with the rest of the chocolate to create shards in a variety of shapes and sizes. Leave until set and hard.
To make the chocolate snowballs: gently melt the chocolate (as above) with the cream then stir until very smooth. Chill until firm then roll into balls of varying sizes in the palms of your hands. Roll the balls in desiccated coconut to completely coat and chill until needed.
Now spread half the remaining buttercream around the sides of the cake and smooth using an offset palette knife or cake smoother. Colour the rest of the buttercream an icy blue shade – using a cocktail stick to add minute drops of the food colouring gel/paste to the bowl. When you have a good colour, spread this blue buttercream over the top of the cake and allow it to extend down the sides a little.
Using an offset palette knife or cake smoother, smooth and blend the buttercream. Peel off the chocolate shards and carefully press them around the sides of the cake. Arrange the snowballs on top and around the cake, then sprinkle with the lustre dust (if using) and the remaining desiccated coconut.