Rainbow Cake


Last weekend my flatmates and I had a BBQ. In my experience, “BBQ weather” is more of a state of mind than an actual temperature in the UK. And though, it was a bit chilly, the sun was out for a little bit and we had a very lovely time eating burgers, drinking cocktails, and stuffing ourselves silly with cake and pavlova.  I wanted to make a fun cake for this event, but it gets tricky sometimes trying to think of a recipe for the blog that’s different from all the other recipes I’ve posted. One of my favourite ways to get around this is to post one of my tried and true recipes with a new twist. Cake of death plus rainbow stripes? Perfection.


As I just revealed, this cake was simply my favourite chocolate cake recipe, the Cake of Death. I didn’t change the recipe except to divide it into four 6″ round baking tins instead of two 8″ round baking tins. I weighed the batter so that I could divide it up equally. I only have two 6″ baking tins, so I just had to wash the tins out after the first two were baked and then bake the final two layers.

The icing is plain vanilla buttercream. I know the general principals of a good buttercream, so I just added sugar until I had the right amount and consistency. It is lusciously fluffy and buttery. The secret to good “American style” buttercream is using all butter and enough butter. Without enough butter, the icing gets pasty and sickly.  The drawback to using all butter is that the final icing is a very pale ivory colour, rather than being pure white. To achieve this pure white buttercream, it must be made with shortening (solidified vegetable fat) and artificial vanilla – neither of which appeal to me very much. I’ll take the slight off-white shade and enjoy the much better tasting icing.


The different colours were made by dividing up about 2 cups/500 ml of the leftover icing and colouring each with food colouring.I drastically overestimated the amount of icing I would need to make the stripes, so I had plenty left over. However, it was easier to pipe the icing with a fuller bag. The stripes were made by create column of petals, exactly as I have described in previous tutorials. There is a photo tutorial here and a video tutorial here. The only difference is to pipe one petal, then pipe the 2nd petal below and slightly overlapping the 1st petal.


Rainbow Cake

Four Layer Cake of Death

Makes 4 x 6″ round layers

Feeds 18-20 people


  • 1 3/4 cups/220g all-purpose flour
  • 2 cups/400g white sugar
  • 3/4 cup/ 90g unsweetened cocoa powder
  • 2 teaspoons baking soda
  • 1 teaspoon baking powder
  • 1 teaspoon salt
  • 2 eggs
  • 1 cup/250 ml strong brewed coffee, room temperature
  • 1 cup/250ml buttermilk (add a few tsp of white vinegar or lemon juice to the milk)
  • 1/2 cup/125ml vegetable oil
  • 1 teaspoon vanilla extract
  • ~200g Maltesers


  1. Preheat oven to 350 degrees F (175 degrees C). Grease, coat with cocoa powder, and line with baking parchment four 6 inch round cake pans. (if you only have two baking tins – like me – just bake the layers in 2 batches and wash the baking tins in between).
  2. In large bowl combine flour, sugar, cocoa, baking soda, baking powder and salt. Make a well in the center.
  3. Add eggs, coffee, buttermilk, oil and vanilla. Beat for 2 minutes on medium speed. Batter will be thin. Pour into prepared pans.
  4. Bake at 350 degrees F (175 degrees C) for 20-30 minutes, or until toothpick inserted into center of cake comes out clean. Cool for 10 minutes, then remove from pans and finish cooling on a wire rack.
  5. Frost with vanilla buttercream and decorate as desired.

Krissy’s Vanilla Buttercream

Makes enough to generously ice one 4 layer 6″ cake


  • 500g unsalted butter, room temperature
  • 1 tbsp pure vanilla extract
  • 850g icing sugar, sifted
  • 3-6 tbsp milk (as needed)


  1. Beat the butter and vanilla together until the butter is fluffy, about 1 minute.
  2. Gradually add in the icing sugar with the mixer on low speed. Add milk as required. Continue slowly adding icing sugar until it is all used up. The amount of milk you may need will vary each time you make the icing. Your icing should be soft enough that you can easily spread it, but firm enough that it holds it shape.
  3. Beat on high for a further 30 seconds until icing is dreamily fluffy. Use immediately.
  4. Optional: Reserve around 500ml/2 cups and divide equally into 6 portions. Colour with food colouring to have red, orange, yellow, green, blue and purple icing. Using a petal tip (e.g. Wilton #103) pipe columns of petals around the cake in a rainbow pattern (as described above). To find out more on how to create the petals, see the blog post and video tutorial.

Happy Baking!


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