Rainbow surprise cake recipe

(44 ratings)

This rainbow surprise cake takes a basic Victoria sponge and upgrades it to a vivid rainbow. It's so easy to do and only takes about an hour to do.

Rainbow surprise cake
Preparation Time30 mins
Total Time30 mins
Cost RangeCheap

This rainbow surprise cake makes a perfect brightly coloured cake for any special celebrations. 

If you love the idea of making a rainbow cake but can't be bothered with faffing about with different colour sponge layers, this is the answer. It's so easy to do - just a basic Victoria sponge recipe - the very simplest of cakes. But the clever buttercream layer in the middle and the pretty spiky icing on the top make it look extra special, especially as you slice it open. We've even created a video, below, to show you how simple it is to decorate. It only takes half an hour to decorate this cake, and you can either use a shop-bough plain sponge, or make your own.


  • 1x 2 layer Victoria sponge cake (sponges only)
  • 600g icing sugar
  • 300g unsalted butter, softened
  • 1 tsp vanilla extract
  • Juice of 1 lemon
  • yellow, pink, red, purple, blue and green food colour gel




  1. Make your basic Victoria sponge cake, sponges only - don't make the filling. Leave the sponge cakes to cool.
  2. Sieve icing sugar into a large bowl and whisk with butter until smooth. Add vanilla extract and lemon juice and whisk again until soft and smooth.
  3. Set out 7 bowls. Weigh 200g into 2 bowls, 150g into 3 bowls, 50g into 2 bowls. Colour each bowl of icing with one colour, leaving one 50g bowl plain, and stir well to combine. Transfer the coloured icings into 6 piping bags and cut a 2cm hole in each.
  4. Pipe concentric circles of each colour on the first layer of sponge and top with the second sponge. Spread a thin layer of plain icing over the top cake - this will help your icing dots stick. Using the remaining icing, dot circles over the top and serve.

Watch how to decorate this rainbow surprise cake

Top Tip for making rainbow surprise cake

Try pastel colours or bright neon colours for the icing to create different effects.

How can I make my own simple Victoria sponge for this cake?

This simple sponge really is the easiest of cakes to make, with equal weights of flour, butter, sugar and eggs. Our basic Victoria Sponge recipe makes it so easy. 

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Jessica Dady
Food Editor

Jessica Dady is Food Editor at GoodtoKnow and has over 12 years of experience as a digital editor, specialising in all things food, recipes, and SEO. From the must-buy seasonal food hampers and advent calendars for Christmas to the family-friendly air fryers that’ll make dinner time a breeze, Jessica loves trying and testing various food products to find the best of the best for the busy parents among us. Over the years of working with GoodtoKnow, Jessica has had the privilege of working alongside Future’s Test Kitchen to create exclusive videos - as well as writing, testing, and shooting her own recipes. When she’s not embracing the great outdoors with her family at the weekends, Jessica enjoys baking up a storm in the kitchen with her favourite bakes being chocolate chip cookies, cupcakes, and a tray of gooey chocolate brownies