This stunning pastel-toned rainbow cake is a guaranteed showstopper. With six delicious layers of moist, rainbow-coloured sponge, vanilla buttercream icing and piped swirls, a pink chocolate drip and finished with a generous scattering of sprinkles, it’s perfect for any special occasion. And while it’s certainly an impressive looking cake, thankfully your Titanium Chef Patissier XL will take care of lots of the hard work for you. Read on for our step-by-step, easy to follow guide to making this ultimate celebration cake, with plenty of hints and tips along the way.
Preparing to bake
This cake serves 8-10 people and takes 4 hours in total to make, including 1 hour cooking time and 1 hour 20 minutes for chilling. Here’s what you’ll need:
Ingredients 1: for the sponges 500g margarine, cubed and at room temperature 500g caster sugar 500g plain flour, sieved 3 tsp baking powder 8 eggs, at room temperature and lightly beaten 2 tbsp milk 2 tsp vanilla extract Salt, to taste
Ingredients 2: to colour the sponges (pastel food colouring shades are easy to find online) 12 drops baby pink food colouring 10 drops peach food colouring 8 drops lemon yellow food colouring 10 drops mint green food colouring 12 drops baby blue food colouring 16 drops lavender food colouring 2 drops baby pink food colouring
Ingredients 3: to make the buttercream 700g unsalted butter, cubed and at room temperature 2 tsp vanilla extract Salt, to taste 1350g icing sugar, sieved 3 tbsp milk White food colouring, as needed (optional)
Ingredients 4: to decorate Pastel coloured sprinkles, as needed 60g pink candy melts 20g white chocolate chips 0.25 tsp vegetable oil Pink or white food colouring, as needed
Tools and equipment Titanium Chef Patissier XL Creaming beater 3 x 18cm (7") round tins 6 x medium mixing bowls 2 x small mixing bowls 20cm (8") round cake board Adjustable sponge cake cutter Turntable Angled palette knife Cake decorating scraper Piping bag x3 Open star piping tip
Get ahead by measuring out your ingredients and prepping your baking area before you start.
Making the base cake batter
Preheat your oven to 170ºC. Grease and line your 3 round cake tins with parchment paper.
Lift the mixer’s head and fit the creaming beater. Attach the mixer bowl to the machine and add the margarine and caster sugar from Ingredients 1 to the bowl.
Start the machine on speed Min and gradually increase speed. Mix on speed 3 for 3 minutes before scraping down the sides of the bowl with a spatula.
Add half of the remaining ingredients from Ingredients 1 (flour, baking powder, eggs, milk, vanilla extract and salt) to the bowl. Starting on speed Min, gradually increase speed before mixing on speed 3 for 1 minute. Then add the remaining half of the ingredients and mix on speed 3 for 30 seconds, or until combined.
Divide the mixture evenly between 6 medium bowls - you can even weigh each portion of the cake batter out to ensure they are the same.
Creating the rainbow cakes
Add a different food colouring to each bowl- pink to the first, peach to the second, yellow to the third, green to the fourth and blue to the fifth. Add both the lavender and 2 drops of pink to the sixth bowl. Stir each one to combine. Scrape the contents of the first 3 bowls into 3 of the prepared tins and spread to level. Bake at 170ºC for 25-30 minutes, until golden brown. Then remove from the oven and allow to cool in the tins for 10 minutes, before turning out onto a wire rack. Leave to cool completely. Repeat with the remaining 3 bowls. Once all the cakes are cool use an adjustable sponge cake cutter to trim and level the top and bottom of each sponge layer. Making the sponges the day before assembling the cake will make it easier to trim and stack them.
Making the buttercream
Attach the clean mixer bowl and creaming beater to your machine. Add the butter, vanilla and salt from Ingredients 3 to the bowl. Starting the machine on speed 1, gradually increase speed before mixing on speed 3 for 30 seconds. Scrape down the sides of the bowl with a spatula.
Add one third of the icing sugar and milk from Ingredients 3 to the mixer bowl. Add white food colouring, if using (this will just whiten the natural yellow colour of buttercream, and is optional). Start the machine on speed 1 and gradually increase speed, before mixing on speed 4 for 30 seconds, until smooth. Scrape down the sides of the bowl with a spatula.
Working in batches, repeat with the remaining icing sugar and milk. Add more milk if the mixture needs loosening up, and mix again.
Assembling the cake layers
Place the cake board in the centre of the cake turntable. Using the angled palette knife, apply a small amount of buttercream to the centre of the board. This is to help keep the cake in place as you layer and ice it.
Place the purple sponge in the centre of the cake board. Transfer some of the buttercream into a piping bag and then pipe a thin layer of buttercream on top of the sponge layer. Use the angled palette knife to level the surface of the buttercream. Place the blue sponge on top and gently press down. Pipe a thin layer of buttercream on top and level, as before. Repeat the process with the green, yellow, peach and pink sponge layers, ensuring the top of the cake is level.
Adding the buttercream
Start by piping vertical lines of buttercream up the sides of the cake, allowing gaps of around 2.5cm (1”) between each line. Dip your angled palette knife in hot water to warm, before drying it off. Hold it flat against the side of the cake and scrape all the way round the outside of the cake to coat it in a thin layer of buttercream, slowly turning the turntable as you work. Try to ensure there are no gaps. Then apply a thin layer of buttercream to the top of the cake. Clean the angled palette knife in hot water again before using it to scrape across the top of the cake, creating a smooth, flat surface. Remove any excess icing from the knife and smooth the top again.
Chill the cake in the fridge for between 30 minutes- 1 hour, until set.
Decorating the cake
Remove the cake from the fridge and place on the turntable. Apply a thicker layer of buttercream to the sides of the cake. Hold the warm, dried angled palette knife flat against the side of the cake so it touches the buttercream and slowly turn the turntable, scraping the sides as you go. Then coat the top with a thicker layer. Clean the angled palette knife in hot water and dry off before scraping across the top to create an even surface. Remove any excess icing from the knife and smooth again. Repeat until the top of the cake is smooth and the edges are sharp.
Clean the edges of the cake board with a damp kitchen towel to remove any excess buttercream. Then, working quickly, carefully press the pastel sprinkles all around the bottom third of the cake with the palm of your hand, working up from the base of the cake. Then put in the fridge to chill for between 30 minutes-1 hour, until the icing is set and feels firm.
Transfer the remaining buttercream into a piping bag fitted with the open star piping tip.
Final stages
Attach the EasyWarm bowl and creaming beater to your mixer. Add the pink candy melts and white chocolate chips to the bowl and fit the splashguard. Select the chocolate melting preset, or mix at heat setting 7 on speed Stir 1 for about 10 minutes, until melted. Pour in a small amount of vegetable oil and stir to combine.
Transfer the mixture into a clean piping bag. Remove the chilled cake from the fridge and place on the turntable. Cut the tip of the piping bag open by approximately 5mm and pipe all the way around the top edge of the cake, so that the mixture drips down the sides. If the mixture is too runny, allow it to chill for a bit longer and try again. Use the angled palette knife to level the chocolate layer on top of the cake and fill in with the remaining mixture. Once the surface is smooth and level, top with a handful of sprinkles before the chocolate sets. Put in the fridge for 10 minutes to set. Then remove and place on the turntable. Pipe swirls of buttercream around the top of the cake and decorate with more sprinkles.
When serving, use a sharp, hot knife (warmed in hot water, then dried) to cut through the firm chocolate layer. This will help prevent the top cracking.
If you liked this you’d also enjoy...
How to make a showstopping celebration cakeRead more
