Chocolate Rainbow Layer Cake

This rainbow layer cake is great for any celebration. The rainbow buttercream is easy to create but is sure to WOW!

10 - 12 slices

Medium 60 Minutes



For the recipe  Chocolate Rainbow Layer Cake

For the Sponge:

165 g Margarine
165 g Caster Sugar
5 ml Dr. Oetker Madagascan Vanilla Extract (1 tsp)
160 g Plain Flour
25 g Dr. Oetker Fine Dark Cocoa Powder (1 sachet)
7.5 g Dr. Oetker Baking Powder (1 1/2 tsp)
3 Medium Eggs (beaten)

For the Decoration:

500 g Unsalted butter
15 ml Dr. Oetker Madagascan Vanilla Extract (1 tbsp)
1000 g Icing Sugar
Dr. Oetker Pink Extra Strong Food Colour Gel
Dr. Oetker Orange Extra Strong Food Colour Gel
Dr. Oetker Yellow Extra Strong Food Colour Gel
Dr. Oetker Green Extra Strong Food Colour Gel
Dr. Oetker Blue Extra Strong Food Colour Gel
Dr. Oetker Violet Extra Strong Food Colour Gel
100 g Dr. Oetker 72% Extra Dark Chocolate
about 20 g Dr. Oetker Unicorn Confetti Sprinkles




For the Sponge

Pre-heat oven to 180°C/160°C Fan/Gas Mark 4. Grease and line 2 x 6” deep round cake tins. Cream together the margarine and sugar until pale and smooth.


Mix in the eggs and Vanilla Extract – if the mixture begins to curdle add a spoonful of flour. Sieve the flour, Baking Powder and Cocoa Powder on top and fold into the mixture until all combined.


Divide the mixture between the cake tins and bake for 40-45 minutes until the cakes have risen and a skewer inserted into the centre of the cake comes out clean. Leave to cool in the tins for 15 minutes and then remove and leave to cool completely on a wire rack.


For the Buttercream

Place the butter in a freestanding mixer a beat until smooth and glossy. Gradually add the icing sugar making sure it is mixed into the butter after each addition. Once all the icing sugar is add the Vanilla Extract and turn mixer upto a high speed. Beat the buttercream until light and whipped in texture. 


Divide the buttercream equally between 6 bowls. Add a different colour to each bowl and mix until the colour is evenly mixed through the buttercream. Place each colour buttercream into a separate piping bag.


Lay a piece of cling film onto your work surface and pipe a strip of each colour buttercream onto the cling film, starting with pink then orange, yellow, green, blue and purple. – make sure the lines of buttercream are not too thick and they should be touching each other. 


Once you have piped a line of each colour buttercream roll the cling film to create a sausage shape. Cut the end of the cling flim to reveal the buttercream at one end. Place the cling film into a piping bag fitted with a star nozzle. 


To Assemble the Cake

Level the top of each sponge and cut in half to create 4 layers of sponge. 


Place the first layer of sponge onto your serving plate or cake board. Pipe buttercream swirls onto the sponge layer and place the next sponge layer on top. Repeat until all the sponges are sandwiched together. If you run out of buttercream refill as above.


Break up the Chocolate and place in a microwavable bowl. Melt the chocolate in the microwave in 30 second bursts, stirring after each burst until melted. 


Pour the melted chocolate onto the top of the cake and spread to cover the cake using a palette knife. Pipe buttercream kisses onto the top of the cake in a crescent moon shape – if you have different nozzle use a variation of nozzles to create different shaped buttercream kisses. 


Sprinkle with Unicorn Confetti Sprinkles to finish.  

Nutritional Information for the recipe Chocolate Rainbow Layer Cake

Per Serving Per 100 g / ml
Energy 4183 kJ
999 kcal
1972 kJ
471 kcal
Fat 54.00 g 25.47 g
Carbohydrate 122.75 g 57.90 g
Protein 4.94 g 2.33 g
Tracking consent

We would be happy if you agreed that we and our partners use cookies and similar technologies to understand how you use our website. This enables us to better understand your user behaviour and adapt our website accordingly. Furthermore, we and our partners would like to use this data for personalised offers on their platforms. If you agree to this, please click on "Agree". Please refer to our privacy policy for detailed information. You can change your mind at any time.

Necessary features

We need these cookies and similar technologies to enable the basic functions of our website. This includes, for example, saving these settings. This is strictly necessary so that you cannot switch this off.

Always active
Analytics and personalisation

In addition, we would like to learn more about how you use our website in order to optimise it for you and other users. To this end, we use cookies and similar technologies that map user behaviour and thus help us to improve our offer for you.



(Re-)Marketing / data sharing with third parties

To ensure that we can tailor our marketing campaigns to your needs, we collect how you come to our website and how you interact with our advertisements. This helps us to make not only our ads, but also our content even better for you. Our marketing partners also use this information for their own purposes, e.g. to personalise your account or profile on their platform.