How To Make A Rainbow Cake

When making a birthday cake or a special occasion cake, you do not only have to think about the outside. Of course the flavour of the cake is one of the most important aspects of the cake however… what if you could make the inside of the cake as amazing looking as the outside of the cake. Well a new concept has graced the cake world and has taken the world by storm. This new and amazing phenomenon is the ‘Rainbow Cake’ deceptively plain on the outside but an array of colours on the inside. Normally, the outside is a white butter cream base covered in ‘Hundreds and Thousands’. As soon as the cake is cut, the colours are unimaginable, usually all the colours of the rainbow interlaced with butter cream, which breaks up the colour.



This is how you do it…


What you will need;


Depending on what colours you would like to use, I usually use the colours of the rainbow (hence the name rainbow cake).

–          Red, orange, yellow, green, blue, indigo and violet food colouring (you can use any type of food colouring however I feel that the gel food colouring pots are the best as the colours come out so strong compared to the high street liquid food colouring and you don’t need as much with the gel pots).

The flavour of this cake will be a simple vanilla sponge so this is what you will need for that…

–          200g Caster

–          200g Plain Flour

–          200g Stork Margarine at room temperature

–          1 1/2 Tsp  Pure vanilla extract

–          2 Tsp  Baking powder

–          3 large free range eggs

–          Non-stick spray

Butter cream ingredients;

–          500g Icing Sugar

–          250g Unsalted Butter

–          2 tsp Vanilla extract

–          4 tbsp Milk

To decorate you will need A LOT of ‘hundreds and thousands’.

Extra equipment:

–          7 mixing bowls (normal bowls will work)

–          7 plastic disposable piping bags with normal round nozzle (if you don’t have 7 nozzles then you can reuse the one you have).

–          7 round 8’’ thin baking tins (again if you do not have 7 then you can reuse one, you will just need to wait until each colour cake is baked individually).


Set the oven to 180C and spay your ‘non-stick spray’ into you 8’’ baking tin/s. Place the stork into a clean bowl and begin to mix. Mixing will take around 5 minutes, you will know when it is done as the stork will turn from a yellow colour to a pale cream colour, when this happens you know you are ready for the next step. Add the sugar to the butter and mix well until all the sugar has been incorporated and the mixture has become light and fluffy. Next, add the eggs one at a time until the mixture has become loose and may even look like it is beginning to split (this is ok as the mix will come together when you add the dry ingredients), add the vanilla extract. In a separate bowl add the flour and baking powder, then slowly add the dry mixture to the wet egg mixture about a 1/3 at a time, ensuring that everything has been mixed in between each addition. Once all of the dry mix has been added to the wet mix, then you are now ready for the fun part…

Get your seven bowls ready and divide the mixture into each of the bowls equally. Then, add which ever food colourings you have chosen to each bowl separately and mix well so that the colouring has been distributed equally and there is no marble effect. Now you have 7 different shades of vanilla sponge mix. Pour each of the coloured mixtures into the 7 different baking tins and place into the oven for around 15 minutes, until you can insert a skewer into the centre and remove it with no gunk on it.  Once the 7 different coloured cakes are ready, remove from the oven and set aside for 10 minutes in the baking tin to cool. Then, remove the cake bases from their tins and leave to cool fully on a wire cooling rack.

Now, whilst the cakes are cooling, it is time to make the icing.

Place the butter into a clean, dry bowl and beat well (just like you did with the cake base right at the beginning). Beat the butter for 5 minutes until it becomes smooth and pale cream coloured. Then, a little bit at a time, add the icing sugar DO NOT USE AN ELECTRIC MIXER just yet as the whole of your kitchen will go from its normal colour to bright white, with the icing shooting everywhere, so be careful. Once you have added all the icing sugar and it has mixed well with the butter, then you can use an electric mixer. Add the vanilla extract and then the milk until you reach the correct consistency as butter cream. Leave to the side and collect you cooled coloured cake bases.

Now it is time to assemble your cake…

Place a small dollop of butter cream on your cake board and place the first colour of your choice on top of the butter cream dollop. The butter cream dollop is only there to keep the cake I place ontop of your board and to keep the structure of the cake. Then once your cake base is ready add some butter cream on top of the coloured cake ensuring that you spread over the surface of the cake evenly. Add the next coloured base on top and repeat this step until all of your colours are on top of each other with a thin layer of butter cream in between them. Once your rainbow cake has been assembled, add the rest of the buttercream around the sides and on top of the cake, until the whole cake is covered in white. Usually, I place this in the fridge for around an hour to set and then go back and add some more butter cream on top of the first layer, around the outside as this makes it look a lot cleaner and ensures that you cannot see the inside colour of the cake. Once you add the second layer of butter cream, now it is the messy part. I usually ensure that I take the cake outside and throw all the hundreds and thousands over it until you cannot see the white butter cream underneath.

Now your cake is ready and all that is left is looking at the face of whoever takes the first piece. Hope you enjoy and if you need any advice or help then please do not hesitate to contact me.

Bye for now!

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