Ingredients

Step by step

1. Preheat the oven to 180°C, fan 160°C, gas 4. Grease and line three 18cm sponge tins. In a stand mixer, beat the butter and sugar slowly until combined, then beat on fast until paler and fluffy. Add the eggs, one at a time, on slow.
2. Add the cooled chocolate to your mixer on slow, then add the peppermint extract. Slowly mix in the flour and baking powder until just incorporated then divide equally among the cake tins, level off and bake for about 30 minutes until just cooked. The cakes should be well risen but still wobble a bit, and a skewer should come out with a little mixture clinging to it. Cool in the tins for 10 minutes (the crust will sink back) then turn out onto a wire rack.
3. For the buttercream, beat the butter and peppermint extract until very creamy and smooth. Gradually add the icing sugar in 4 batches, beating slowly so that the icing sugar doesn’t puff up everywhere, adding 1 tablespoon of boiled water after each addition, then turn up to high speed for a minute or so. This makes it extra creamy and fluffy.
4. To assemble, leave the crackle top on the cakes if they are quite flat, or trim to level off if you need to. Place one cake on a turntable or cake stand (fix with a smidge of buttercream to secure) and use a palette knife to spread with some buttercream. Top with a second cake and more buttercream. Place the last cake on top, flat base uppermost.
5. Generously spread buttercream all around the sides of the cake first (this means you can hold the top of the cake still while you work). Once the sides are covered, spread a thin, even layer over the top of the cake.
6. Now clean the palette knife and go around the cake again to smooth off the excess covering, spreading it until you are happy that it’s nice and neat, as a crumb coat base. Pop the cake into the fridge to firm up for 30-60 minutes.
7. To add the frosty fault-line detail, use a small crank-handled palette knife to spread a thin band of buttercream around the middle section of the cake; make the edges wobbly, like a crack in the ice. Press the sprinkles into this frosting to create a shimmery ice effect then place back in the fridge to set firm.
8. Make the penguins’ bodies from ovals of black and white icing to match the picture (brush lightly with water to help the white icing stick to the black). Add tiny eyes, then little orange beaks and use a knife to make a little smile. For the scarves, twist thin sausages of blue and white icing together like a rope, flatten, and cut into little strips. For the hats, simply mould with fingers from blue icing and sit on top of the head, add a little ball for the bobble and texture with the end of a small fork or cocktail stick for the detail. Set the penguins aside.
9. Tint the remaining buttercream a very light ice blue with a smidge of colouring. Remove the cake from the fridge and brush off any loose sprinkles. Using a small palette knife, dollop a thick coating of buttercream below the band of sprinkles, letting it go slightly over the edge of the band and making it quite jagged like a crack. Go around with the palette knife to smooth this band down evenly, scraping away any excess. Do the same above the sprinkle band, then ice the top of the cake.
10. Use a cake scraper or the side of a large palette knife to smooth the top and the side of the cake, turning the cake as you go and slightly edging the blue icing over the sprinkles to create the impression of a fault-line in ice. Don’t worry about the edges being too neat – a rough edge adds to the cracking-open effect. Spritz with silver glitter spray for an icy look.
11. Chill again to set. Trim the bottoms off some of the penguins at different heights to make it look like they are popping out of the thicker frosting against the icy background. Dab a little buttercream on the backs of the penguins and press on gently to fix.