Rainbow Layer Cake

My nephew’s first birthday and of course, my hand shot up in offer to make the Birthday cake, in complete disregard of anything that might get in the way of this. As it turned out, something big did get in the way of it – my job.

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So the Birthday party was on a Friday night, and I work regular Monday to Friday hours – no big deal, I can make the cake in the evening, except this particular week I had an event on Thursday night, which meant I’d be staying at the office until at least midnight! But I really, really wanted to make this cake, and by this cake, I mean a five layer rainbow cake with Cream Cheese Swiss Meringue Buttercream (a type of frosting that doesn’t actually exist, and for a good reason!), not an easy feat at the best of times… but I was determined… and stubborn.


I made the cake layers on Wednesday night, wrapping them tightly with baking paper and cling wrap to keep them fresh, and then got up at 5am on Friday (after working till midnight the night before) to assemble the cake. As I said, stubborn. I was so stoked with the result it wasn’t even a chore for me, I wanted to do it, I loved doing it, I just wish I’d had more time to enjoy doing it! The decorating job left something to be desired, but (surprisingly) it was not a total disaster – I have an unsteady hand at the best of times so was quite baffled when I realised I’d piped my One straight!


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Vanilla Rainbow Cake Recipe


2 1/2 cups plain flour
5 tsp baking powder
1/2 tsp salt
2 cups sugar
4 large eggs
1 cup rice bran oil
300ml buttermilk
50ml whole milk
3 tsp vanilla extract
purple, blue, green, yellow, and red food colouring


Preheat your oven to 165°C/325° F/Gas Mark 3, then grease your 20cm round cake tins and dust with flour.

Start with your dry ingredients, combining the flour, baking powder and salt in a medium sized bowl.

Take a larger bowl and whisk together the sugar, eggs, rice bran oil, buttermilk, milk and vanilla. Add eggs one at a time and beat after each addition.

Divide your batter evenly into 5 bowls – If you have a kitchen scale, weigh them out and they’ll be perfectly even!

Add enough food colouring to each bowl so that you have a nice, vibrant colour – your cake will be the colour it looks in the bowl.

Your cake layers will seem quite thin, but don’t worry, they puff up nicely with all that baking powder and the result will be a beautiful light cake, with the oil keeping it lovely and moist.

I baked each cake layer for about 25 – 30 minutes, but this will depend on your oven so keep an eye out after 20 minutes – they won’t need long! Your cakes are ready when the skewer comes out with cooked crumbs attached to it, or when it comes out clean!

Swiss Meringue Buttercream

I actually made a cream cheese SMB for this cake, but as it was a trial and error thing that was mostly error (took me three hours to get it back!), I will just give you the SMB recipe.


9 large egg whites
2 cups sugar
2 1/2 blocks (625g) of butter, room tepmerature
3 tsp vanilla extract


Gently heat the sugar and egg whites over a double boiler until the sugar has dissolved completely.

Remove from heat and beat the mixture to stiff peaks. Continue to beat until the bowl has cooled to room temperature. You should have a bowl of thick, glossy, stiff egg whites.

Cut the butter into cubes, it should be firm enough to hold it’s shape, but should not be cold. Add the butter to the egg white mixture a little at a time beating continuously with the paddle attachment. Your mixture will collapse a little and may look a bit of a soupy mess but don’t worry, just beat, beat, beat – it will come together in the end.

Once your SMB has reached it’s thick, glossy peak your ready to assemble your cake. For detailed instructions on filling, crumb coating and frosting read this post.

Enjoy… x


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