Instructions

1. We recommend making the unicorn ears and horn a few days in advance to give them a chance to dry and harden. Tip: You can also add a bit of tylose powder, bought in cake supply stores, to the gumpaste which will help it dry and harden quicker. You can also use Mexican modelling or flower paste.
2. Dust a surface with cornflour then knead the gumpaste until it’s soft and pliable. Roll it out to about 5mm thick, then cut out 2 pointed ear shapes, about 7cm in height. Tip: We find it easier to cut out the one shape, then use the cut-out ear to trace and cut out the second ear so that they match each other. Cut out 2 smaller versions, about 5cm in height, which will be the inner-ear.
3. Wrap up remaining gumpaste and set aside. Lightly wet the back of the smaller ear shapes with a bit of water, then stick them to the larger ear shapes, lining up the bottom edges. Pick up each ear and bend slightly in the middle, vertically, to help give them shape. To dry, leave them propped up in something like an empty egg carton.
4. Finally, paint the inner-ear section with edible gold paint or lustre dust. Leave to dry.
5. For the unicorn horn, quickly knead the remaining gumpaste until soft and pliable, then roll into a long, smooth rope, getting thinner at the one end which will be the tip of the horn. Stick the skewer into a small cake dummy or similar so that it’s standing up. Brush the skewer with water, then wrap the gumpaste rope around and up the skewer, starting with the thickest part of the rope at the bottom, until the skewer is hidden. Carefully remove the skewer from the cake dummy or similar, then gently roll the unicorn horn on a floured surface.
6. Spread the rings of the gumpaste slightly, then lightly wet in between with a bit of water. Press the rings back together so that there are no gaps, the water will help the gumpaste stick together. Carefully prop horn upright, using the same cake dummy or similar, and leave to dry. You can either paint the horn gold with edible paint or lustre dust while it’s drying, or you can paint it once it’s placed on the cake.
7. To assemble the cake, have your cake sponges cooled and trimmed so that they’re level. Tip: 18cm (7”) cake tins are a bit unusual, but we find that the unicorn cake looks nicer when it’s taller rather than wider. You could also trim the sides of 20cm (8”) sponge so that they become 18cm in diameter.
8. Make the vanilla buttercream (we doubled this recipe). Tip: We used white gel colouring to help whiten our buttercream. It won’t make a pure white buttercream, but we like the look of the pale cream/ivory colour much more than the yellow of plain buttercream. You can buy white gel colouring from baking supply stores.
9. Place one of the sponges on a cake plate or serving dish. Spread about 1/3 cup (80ml) buttercream over the top of the sponge, then gently place the second sponge on top, gently pressing down to make sure it’s sitting properly and is level. Repeat until you place the final sponge on top.
10. Coat the entire cake with a crumb coating of buttercream, which is just a very thin layer of buttercream used to trap any stray crumbs. Place cake in the fridge and allow crumb coat to firm up, about 15-20 minutes. Once crumb coat is set, remove from the fridge. Give the remaining buttercream a quick mix with a spatula, then finish icing the cake with a thick layer of the frosting. Tip: Use a bench scraper to get lovely smooth and straight sides, and a smooth and level surface. You can see this being done in our video. Return cake to the fridge to firm the frosting.
11. Remove about 1 tbsp of buttercream and place in a small bowl. Then divide the remaining buttercream icing into 4. Leave one portion of buttercream white, then colour the other portions with any colours you like using gel or paste food colouring. We used pastel pink, blue and purple. Spoon each portion of buttercream into a large piping bag, each fitted with large star piping tips. Colour the reserved 1 tbsp of buttercream with black gel or paste colouring, then spoon into a piping bag fitted with a small plain piping tip. Tip: You can buy ready coloured black buttercream from cake supply stores, they’re usually in tubes. You could also buy black piping/decorating gel instead.
12. Remove the cake from the fridge then stick the unicorn horn in the centre of the cake. If you haven’t painted it yet, do so now. Then stick the 2 ears on either side of the horn.
13. Now, pipe large swirls of buttercream in front of the horn and ears to start the mane, alternating the colours. You can also pipe some swirls on top of swirls to give a bit of height. Pipe a large “S” shaped swirl right at the front of the cake, coming down over the side, this will be the fringe.
14. Turn the cake around and pipe large swirls of frosting behind the horn and ears, working your way down the side of the cake, so that when you’re looking at the cake from the front, you’ll see the lovely coloured swirls down the one side. Use the black buttercream to pipe on closed eyes with eye-lashes on the front of the cake. Then finally, decorate with sprinkles, edible glitter or wafer flowers.