Taste The Rainbow surprise cake

I’ve recently joined a local cake club and decided to go along my first meeting. Each time the club meets, there is a theme and you bring along a cake to match with that. This time, the theme was ‘Surprise Surprise’. After spending some time thinking about what to make, I decided to go with a double surprise and came up with this Taste The Rainbow cake. Inside the actual sponge is dyed in bright colours and the centre of the cake is hollowed out then filled with rainbow hued sweeties!

Taste The Rainbow cake.

Taste The Rainbow cake.

This cake is actually a lot easier to make than you might think and would make a perfect centre piece for a child’s birthday party.

I made a very large cake to ensure everyone at the event could have a slice and this is what you will see in the photographs. However, the quantities I’ve given below will make a cake half the size of mine. You can easily double up the amounts if you are also feeding a lot of people or having a large party.

For the cake you will need:

  • 8oz soft margarine
  • 8oz sugar (caster or granulated)
  • 8oz self raising flour
  • 2 teaspoons baking powder
  • 4 eggs
  • Gel food colouring (if you want coloured cakes)
  • 2 round 8inch cake tins
  • Greaseproof paper
  • Electric hand mixer or stand mixer

For the buttercream you will need:

  • 6oz soft margarine
  • 12oz sifted icing sugar
  • Electric hand mixer or stand mixer
  • A disposable piping bag and large plain nozzle (these are not essential as you can use a knife to spread the buttercream)

For decoration you will need:

  • 2 large bags of skittles sweeties. You could also use smarties or any other sweets you like.
  • 1kg pale blue fondant/sugarpaste. Alternatively, you can use white fondant and add some blue food colouring gel.
  • A small amount of fondant/sugarpaste in each colour of the rainbow (red, orange, yellow, green, blue, indigo and violet). Again, you can use white fondant and add colouring gel. Or use some of the pre-coloured fondant to make other colours. For example, I mixed some red and yellow fondant together to make orange.
  • A small pack of white fondant/sugarpaste.
  • Some icing sugar for dusting your work surface.
  • A rolling pin.
  • A sharp knife.
  • A fondant smoother if you have one. If not, your hands will do the same job!
  • A cake board, stand or plate big enough for the finished cake.
  • Some greaseproof paper
  • A little bit of edible glue or water.
  • A small paintbrush (make sure it’s clean!).
  • Cloud shaped cutters. If you don’t have these, you can cut them out free-hand or make a template.
  • A sun shaped cutter. Again, you can cut this out with a sharp knife if you don’t have a cutter.
  • A palette knife.


How to make the cakes:

1) Pre-heat the oven to 160 degrees centigrade. Grease the two cake tins and line the bases with greaseproof paper.

2) Put the margarine, sugar, flour, baking powder and eggs into the bowl of your mixer. ¬†Starting on low speed, mix all the ingredients together. Increase the speed to medium for a couple of minutes until the mixture is smooth. Do not over-mix though or you won’t have a light, fluffy sponge.

3) If you want to colour your sponge cakes, now is the time to do it. To get two different colours, separate the mixture into two bowls. Add a little gel food colouring to each bowl and gently, but thoroughly, fold into the batter with a spoon. Make sure there are no streaks of colour.

4) Put the mixture into the prepared tins. Smooth out with the back of a spoon so the mixture is level.

5) Bake for approximately 25 minutes or until the cake springs back when pressed lightly with your finger. If you are unsure whether the cake is cooked, insert a cocktail stick into the sponge – if it comes out clean, the cake is ready. If there is any batter on the cocktail stick, place the cake back into the oven for 5 more minutes, then check again.

6) Leave the cakes in the tin for 10 minutes or so. Then turn them out onto a wire rack, peel off the greaseproof paper and leave to cool completely.

To make the buttercream:

1) Place the soft margarine in the bowl of your mixer. Beat until very soft.

2) Add in half of the sifted icing sugar. Starting on a very low speed (to avoid an icing sugar cloud covering your kitchen!), mix the icing sugar into the softened margarine. Increase the speed and mix a little.

3) Add the rest of the icing sugar. Again, starting on a very low speed, begin to blend the sugar into the margarine. Increase the speed gradually until it is on high. Continue to blend on high speed for several minutes until the buttercream is very light and fluffy. You can add in some food colouring at this stage if you would like to make different coloured icing.

4) Snip the end off the disposable piping bag and insert the plain nozzle. Spoon the buttercream into the piping bag and twist the top.

Assembling the cake:

1) Using one of your cake tins, draw round this onto some greaseproof paper. Cut out the circle then fold in half and cut along the fold.

2) Take each of your cakes in turn. Place the semi-circle of greaseproof paper over one half of your cake. This will give you a guide to cut the cake into two equal halves. You will now have 4 semi-circular cakes. Put these to one side.

Cut each cake in half.

Cut each cake in half.

3) Get your semi-circle of greaseproof paper and draw a smaller semi-circle within it, about 1 to 1.5 inches in from the edge. Cut this shape out.

Cut out a smaller semi-circle.

Cut out a smaller semi-circle.

4) Take one of your sponge cake halves. Place the smaller semi-circle of paper in the centre of your cake. Using a sharp knife, carefully cut round the template and remove this piece of cake. You won’t need this part of the cake so why not crumble it up and use it to make some cake pops.

Remove the centre of two cake pieces.

Remove the centre of two cake pieces.

5) Repeat with one of the other cake halves. If you have made two coloured sponges, ensure you cut pieces out of two different coloured cakes to give a stripy, rainbow effect.

6) You should now have two complete semi-circles of cake and two pieces of cake with the centres removed.

7) Take one of the whole semi-circles and pipe (or spread) some of the buttercream along the edges.

8) Place one of the cakes with the centre removed on top and gently press down to stick them together. Pipe some more buttercream along the edge then add the other cake with the centre removed on top. Again, pipe more buttercream onto the edges.

9) Pour in the skittles (or other sweets) until they fill the cavity of the cake. You may need to support the cake with your hand.

10) Finally, place the second full semi-circle cake on the top.

11) Carefully flip the cake onto it’s flat edge and place on the cake board or serving plate.

Assembling the cake.

Assembling the cake.

12) Pipe buttercream over the whole surface of the cake. Spread out with the palette knife so the cake is completely covered. Smooth over this with the knife, removing any excess icing, until there is a thin, even layer of buttercream.

Cover the cake with buttercream.

Cover the cake with buttercream.

13) Put the cake in a cool place (not the fridge) for a few hours until the buttercream hasset and formed a bit of a crust. Your cake is now ready for decorating.

Covering the cake:

1) Take the pale blue fondant and knead this a little until it is soft and pliable. Dust the work surface with some icing sugar. Also, sprinkle a little on top of the fondant.

2) Roll out the fondant, moving it often to avoid sticking, until it is about 3-5mm thick. Check that your rolled out fondant is large enough cover the cake.

3) Have the cake, a sharp knife and the icing smoother (if you have one) to hand. Using the rolling pin to help you, lift the fondant over the top of the cake and carefully let it drape down the sides.

4) Working quickly but carefully, use your hands to smooth the fondant over the cake, easing out any folds. Trim away the excess fondant but don’t go too close to the edge of the cake yet.

5) If you have an icing smoother, rub this firmly over the fondant across the top and sides of the cake. Alternatively, use your hands to do this.

6) Carefully trim the icing very close to the bottom edges of the cake then smooth around this area.

Covering the cake in fondant.

Covering the cake in fondant.

Decorating the cake:

1) To make the rainbow, firstly turn one of the cake tins you used upside down and cover with some greaseproof paper. Roll out a long thin sausage of red fondant icing. Place this on the up-turned cake tin, slight in from the edge, and bend it to follow the curve of the tin. Using the brush, paint a little bit of edible glue (or water) on the bottom edge of the red icing strip. Now roll out a long thin sausage of orange icing and attach this to the bottom of the red icing with a little glue as before. Repeat this for all the colours until you have a complete rainbow. Set to one side and allow to dry, preferably overnight.

Create the rainbow.

Create the rainbow.

2) For the clouds, roll out some white fondant on a work surface dusted with icing sugar. Use the cutters to stamp out different sized clouds. You can cut these out free-hand or cut round a template.

3) Roll out some yellow or orange fondant and cut out a sun.

4) On the back of the rainbow you prepared earlier, paint a thin layer of edible glue or water. Stick the rainbow to one end of the covered cake. You may need to support this with your hand for a little bit until the glue starts to set.

5) Decide where you would like to place the sun. Paint a little edible glue on the back of the sun then stick it to your cake.

6) Put some glue on the back of each cloud and then attach these to the cake. You could also add a few to the cake board/plate.

7) If you like, you can add a little bit of edible shimmer or lustre dust to the sun and clouds. This will give them a bit of added texture.

Taste The Rainbow cake.

Taste The Rainbow cake.

Your cake is now complete!! I really hope you enjoyed making this and have fun seeing people’s reaction when you cut into the cake!



Happy baking!


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