I have always wanted to make a Rainbow Cake and I decided that my birthday this year was the perfect occasion! Instead of vanilla flavour, I went for a Lemon Rainbow Cake because it’s such a large cake I thought it would be too sweet to do the whole thing vanilla. The lemon zest in the sponge and the lemon curd between each layer cut perfectly through the sweetness so it’s not overwhelmingly sweet to enjoy a slice of this Lemon Rainbow Cake. Of course if vanilla is your thing, then you can easily make this cake a vanilla Rainbow Cake too!
I own three 8″ cake tins so I did three layers of the cake at a time, I started by creaming the butter and sugar together with the lemon zest.
Then I added the eggs and self raising flour, and split the mixture between three bowls.
I mixed in the food colouring, divided the mixture between the tins, then baked them.
After washing the tins, I did the same again for the other three colours.
To make the buttercream I mixed together the butter, icing sugar and some vanilla extract.
Between each layer I spread a thin layer of buttercream, then drizzled some lemon curd over the top.
Once the sponges were all stacked and filled with buttercream and lemon curd, I covered the whole cake in a thin crumb coat of buttercream. It then went in the fridge for an hour to firm up.
I spread on a final layer of buttercream and smoothed it out. Usually I would do this on a turn table, but as I was adding sprinkles to the bottom I wasn’t too concerned about absolute neatness!
My family and friends loved this Lemon Rainbow Cake, and it was very popular at my birthday party. It even did well against my favourite cake of all time which was also on offer – Chocolate Guinness Cake with Baileys Buttercream!
You get quite a large slice of the Lemon Rainbow Cake even if you cut quite a thin slice, purely because of the height of the cake. But the lemon curd and lemon zest in the sponge stop it from being too sweet, which is exactly what I wanted.
I’m linking this recipe up with Cook Blog Share hosted by The Peachicks Bakery, Cook Once Eat Twice hosted by Searching for Spice, and Fiesta Fridays hosted by The Not So Creative Cook and Of Goats & Greens.
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Lemon Rainbow Cake
For the sponges
- 550 g Butter or baking spread
- 550 g Caster sugar
- 4 Lemons zest only
- 10 Eggs large
- 550 g Self raising flour
- 2 tbsp Milk
- Red, yellow, orange, green, blue and purple food colouring I used Rainbow Dust
For the buttercream and filling
- 600 g Butter or baking spread
- 1.2 kg Icing sugar
- 2 tsp Vanilla extract
- 275 g Lemon curd
- Rainbow sprinkles
I own three 8" cake tins so I did three layers of the cake at a time. Only make as much mixture as you have cake tins for as you must not leave cake batter sat for a long period of time as it will affect the final result. You can also buy disposable foil cake tins if you don't want to invest in more cake tins, but I recommend having at least three of the same size as there are lots of cake recipes on my blog that require three 8" tins
Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and grease and line your 8" cake tins
Make the first three sponges by mixing half of the butter and caster sugar in a large bowl with a spoon until fluffy, or mix using an electric mixer
Add half of the eggs, milk and vanilla extract, and whisk until fully incorporated
Add half of the self raising flour and whisk in until you can't see any flour anymore
Divide the mixture equally between three bowls, add red food colouring to one bowl, orange to another and yellow to the last one. Whisk until the desired colour is achieved
Divide the mixture between the tins and bake for 20 minutes or until a skewer inserted in the middle comes out clean. Remove from the tins and leave them to fully cool on cooling racks
Wash the tins, re-line and grease them, then repeat steps 3 - 7 but add the green, blue and purple food colouring instead
To make the vanilla buttercream mix the butter and icing sugar together. Once it starts to come together add the vanilla extract and mix until smooth. I use my electric hand whisk to do this but you can also do it by hand with a spoon
Start stacking the sponges on a plate or turn table. Spread a thin layer of buttercream onto each sponge, followed by a generous drizzle of lemon curd, before adding the next one
Once the sponges are all stacked and filled with buttercream and lemon curd, cover the whole cake in a thin crumb coat of buttercream. Put it in the fridge for an hour to firm up
Remove from the fridge and spread on a final and thicker layer of buttercream and smooth it out
Put the remaining buttercream into a piping bag fitted with a nozzle of your choice and pipe some small rosettes around the edge of the cake
Fill the middle of the top of the cake with rainbow sprinkles, and use a brush or your hands to add more sprinkles to the bottom edge of the cake
Leftovers will keep in an airtight container for 3 days
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