As it was Jaxon’s 3rd Birthday last week, it was only right to go ahead and bake him an amazing birthday cake! I had been hunting over on Pinterest for inspiration and ideas for his birthday cake, but never came across anything that blew me away, until I saw The Rainbow Cake! 🌈 I have seen this cake before and it’s quite a popular cake in bakeries, but I had completely forgotten about it until I saw it again. I knew this cake would be a challenge because of all the rainbow cake layers, and I had never done this before. I knew if I pulled of this cake for Jaxon’s Birthday it would be amazing. (No Pressure!!) I have to say that my first attempt at this colourful creation wasn’t a disaster and Jaxon just loved it!!
So I thought I would share the recipe on how I made Jaxon’s 3rd Birthday Cake! It did take me most of the afternoon to make but it’s definitely worth doing! So without further ado here is the Recipe!
For the Cake:
- Whole Milk – 9 tbsp
- Vanilla Extract – 1 1/2 tsp
- Various Colour Pastes – Red, Orange, Yellow, Green Blue and Purple.
- Soft Unsalted Butter – 750g
- Large Free Range Eggs – 9
- Self Raising Flour – 750g
- Butter for preparing the cake tins
- Sprinkles to decorate
For the Buttercream:
- Unsalted Butter – 400g
- Icing Sugar – 900g
- Whole Milk – 5-6 tbsp
- Vanilla Extract – 1/2 tsp
- Six 8inch Baking Tins
- Six Bowls for each different food colouring
- Electric Scales
- Serrated Knife or Cake Cutter
- Spatulas, palette knife, crank palette knife and Cake Scraper
- Extra bowl for measuring and the cake batter
- Baking parchment.
- Cake board or Plate displaying the Cake
The Off Cut – Don’t worry it didn’t go to waste!
- Pour 9 tbsp of whole milk into a jug and add 1 and 1/2 tsp of Vanilla Extract and then mix them together. Once your have done that, then you need to divide the milk mixture into six, which is 1 and 1/2 tbsp each. Add the 1 and 1/2 tbsp of whole milk to the six separate bowls. And then add a bean size amount of each of the six colour pastes. (Red, Orange, Yellow, Green, Blue and Purple.) Mix the milk and colour pastes together until you have six vibrant colours. By using the colour pastes they are much more concentrated than liquid food colouring, which gives it that vibrant colour you need for this cake. Once the colours are all mixed, pop them to one side for later when you are ready to use them.
- Now you need to make the batter, so you need to add 750g of softened unsalted Butter into the mixer with 750g Caster Sugar. Mix on a medium to high speed for about 6-7minutes until it’s gone really pale and fluffy. Then crack 9 large free range eggs into a bowl and whisk them, then add them into the mixer on a slightly slower speed, adding them in 5-6 stages, mixing quite well between each one. If you find your mixture curdling, you can add a bit of your flour; a tbsp should do, and that will help it bring it back together again. Add 750g to the mixture and put on a really low speed setting.
- Next grab a set of electric scales, and place an empty bowl onto the scales, and then put the whole cake batter into that bowl, to measure the whole amount you have got, once you have your amount you need to divide by six. Then you need to put each amount you have into the six bowls, which should be all divided equally as you have worked out the correct amount. Using a spatula, you need to mix each of the six colours with their batter. When you are mixing the colours with the batter, just be careful not to knock out some the air you have created in your cake mixture. So fold gently.
- Preheat the oven to 170C and Butter six 8 inch cake tins. Then scoop each of the coloured mixture into the six tins and level each one off with a crank palette knife. You should have Red, Orange, Yellow, Green, Blue and Purple in each tin. Then you need to bake them at 170C for 20 mins until a skewer comes out clean. Once baked leave aside to cool.
- Now you need to make the white vanilla buttercream, for this you need to start with 400g of softened unsalted Butter and you need to beat this really fast for about 5 minutes, until it’s gone really pale and fluffy. Then you need to add 900g of icing Sugar, so you need to put it into the mixture in two stages and beat for about 2 minutes between each one. Add 5tbsp of whole milk to a jug and then add 1/2 of tsp of Vanilla Extract and mix together. Then add the milk to the buttercream mixture on slow speed and then beat it on quite a high speed for another two minutes. Place some cling film over your bowl of buttercream until you are ready to use.
- Place each cake onto some baking parchment, this makes it easier for you to move the cakes around instead of you keep on lifting them up which may cause some breakage to the cake. Now you need to trim and cut your cakes so do this, you can use a serrated knife or a cake cutter. If your using a cake cutter, you can set it on to notch three which is just under an inch high for each level. So starting with the red cake, cut each top of the cake and continue to do this until all your cakes have been cut. Now you need to cut the edges off your cakes, so you need something smaller than the diameter of your cake. (I used a small bowl) place it on top of your cake and trim it all the way round, very gently, and remove the outer crusty bit, so you have a nice clean edge. Continue to do this for the rest of your cakes.
- Get your cake board or plate and place it onto a turn table, this will be easier for you to use when you come to ice your cake and it will give you nice straight sides too. Put a third of your buttercream into a bowl, because you don’t want it to get too crumby. Grab a crank palette knife and put a little buttercream onto your cake board or plate, this will secure the cake in place and stop it from moving. Starting with your purple level, pick it up really gently using your whole hands and put it right in the middle of the cake board or plate and give it a little press down so it’s securely in place.
- Now you need to give your purple cake a little crumb coat, which will lock in all the crumbs before adding a thicker layer of buttercream. Grab a little bit of buttercream on your crank palette knife and and spread a thin layer on top of the cake. Once you have a nice thin layer, you need to fill the cake properly. Add a generous blob of buttercream and spread evenly all over. Now you need to continue this pattern, by adding the rest of the cake layers with blue, green yellow, orange and finishing with red. Now your cake is filled, you need to give it a crumb coat, so when you come to decorate it for real, it’s nice and clean and crumb free. Smear some buttercream all over the cake, nice and tight so that the cake will be crumb free. It doesn’t have to be a thick layer as you will be putting a thick layer on top a bit later. Make sure you lock in all the crumbs and the edges are nice and smooth. Once you have done that, put the cake into the fridge for about 1-2 hours. This will set the coating and make it smooth for the final layer.
- Remove the cake from the fridge and place back onto your turntable, and then taking the remaining buttercream you made earlier, you want to spread about half a cm of buttercream onto the cake, and then using the cake scraper, smooth it over and scrap of any excess back into the buttercream bowl, continue to do this all over the cake until it’s completed covered.
- Finally to decorate your cake sprinkle on some hundreds and thousands all over the top and around the sides.
And there you have it, the recipe on how to make the perfect Rainbow Cake. The real test is obviously cutting into the cake, and seeing all the amazing layers. This was such a big cake to make, but I thoroughly enjoyed making it, especially for Jaxon’s 3rd Birthday!! Let me know if you make it, and tag me on Instagram @thecountrysidemama as I would love to see your bakes!
See you soon!