This is a great showstopper for birthdays whether the guest of honour is a kid or just young at heart.
It may look refined from the outside, but on the inside it’s completely mad. Like all of the best people.
Mum used to make it for our birthdays when we were little. She would top mine with iced roses and I still remember the butterflies of excitement as we’d cut into it to reveal the marbled rainbow inside.
“How do you do that?!” we’d ask.
“Magic.” was invariably her knowing response, and one we accepted without question.
Now I’m old enough to understand, I can say for certain that she was quite right. This recipe does require a good dollop of magic. I think mine came from the excitement of staying up late to bake my daughter’s first birthday cake. The tingling excitement and little voice in the back of my mind that says “you’re a real mum now.” Funny how it’s reliving things our parents did that really hammer it home. Whenever I pull up at a stop sign and reach back to pick up the dropped bunny blanket I have the same feeling. Much like the grinch, I feel my heart grow a size each time.
I thoroughly recommend baking this the night before the party, glass of wine in hand, retro playlist on the stereo, dance your way through the steps. It’s where the magic comes in!
I like my cake to look dignified on the outside and wild within, but you could absolutely go crazy with rainbow sprinkles if you prefer!
The rainbow marble effect will work with any light coloured cake batter. I made an orange sponge, but even a box vanilla kit will do the job. Here’s what I used:
For the cake:
2 x 8in cake tins
340g (12oz) self raising flour
340g (12oz) unsalted butter (room temp)
340g (12oz) caster sugar (granulated)
1tsp baking powder
Juice + zest of 1 orange
Food colouring (4 colours)
For the icing:
250g cream cheese (in US get “cream cheese spread” rather than a block)
50g butter (room temp)
100g Icing/powdered sugar
Juice + zest one lemon
Pre-heat your oven to 175C/350F. In a large bowl beat together your butter & sugar until creamy. Add your eggs one by one, beating until smooth. Add your dry ingredients bit by bit, add your orange. Beat until you have a smooth batter. Now split into four bowls. Add a few splashes of colour to each bowl.
Beat until each looks like something the Lost Boys would enjoy.
Be sure to clean your whisk/spoon/processor each time, so the colours don’t mix into each other. I find it best to use a hand mixer, as it’s easy to rinse the beaters.
^Hopefully you won’t have such huge chunks of orange zest, I only have a cheese grater here!
Once you have 4 bowls of coloured mix, grease your tins with a bit of butter.
Spoon a dollop of each colour into the pans. Keep going until they’re about half way full.
Grab a clean spoon and gently swirl the colours together, not so much that they start to mix, just enough to marble them.
Pop into the middle of your oven for about 25-30mins. When they’re done, you should be able to slide a skewer or sharp knife into the middle and have it come out clean.
Leave to cool on a wire rack until room temp. While you wait you can make your icing.
Blend your cream cheese, butter, sugar and lemon together until smooth. It helps a lot if the butter is room temp, don’t try it with fridge fresh butter. Taste test, see what you think. I like my icing a little tart, but you can add a little sugar if you prefer.
Once cool, grab a breadknife and carefully level the cakes by slicing off the domed tops.
Go little by little, remember you can always cut more away!
Don’t worry about them being perfect. Good enough is good enough.
Place your base layer on a cake stand or plate. Add a good dollop of icing, smooth it across the top and sandwich your second cake on top. Cover with icing and smooth it out a bit.
I don’t have any fancy equipment, I used a spoon but you could make it perfect with a pallet knife.
Decorate however you fancy, I stuck with the citrus theme.
Don’t tell anyone what’s hidden away inside, save it for the cake cutting!
Slice into it…
…and reveal the rainbow inside, to lots of appreciative “ooo”s.
Just remember, if anyone asks you how you did it, tell them the truth.