Pastel Confetti Rainbow Cake

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Pastel Confetti Rainbow Cake

The time had come to make Lizzy’s 20th birthday cake and I was feeling more than a bit daunted by the prospect. I knew it was going to be admired (hopefully) and wolfed down by zillions of her cool, studenty friends, but I can never shy away from a cake challenge. So, the question was, what to do?!

I’ve had a pack of these adorable pastel confetti sprinkles knocking about in the cupboard for a while now, just waiting for the perfect cake to adorn.

confetti sprinkles cake

Pastel Confetti Sprinkles

I knew I just had to use them for Lizzy’s cake, they are so ‘her’ – sweet, girly and fun. Together with the Barry M nail polishes I gave Lizzy for her birthday (aren’t they so pretty and summery?) it all started becoming clear….a pastel cake of some description was in order.

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Pastel Nail Polishes

I’ve dabbled with multiple layer cakes in the past. Here is the Neapolitan cake I made for a Clandestine Cake Club ‘ice cream’ theme gathering. If you haven’t heard of the Clandestine Cake Club yet, have a look at their website – there might be a club near you. It’s all about cake!

Neapolitan Cake

Neapolitan Cake

I made this bright rainbow cake for my daughter’s 1st birthday after seeing it on Whisk Kid‘s blog.

Rainbow cake

Rainbow cake

Having just about recovered from that bake-athon, (2 years later ;)) I had recently started toying with the idea of making another one, only this time I knew exactly what I would be taking on!

And thus, the pastel confetti rainbow cake was born…..

Warning – this is not a cake for the faint-hearted, either to bake or to eat.

The effect is not too difficult to achieve (shhh), and the results are simply stunning. It does take A LOT of patience to bake all the layers, and, if you have perfectionist tendencies (like me) it can be a tad stressful in the assembly! I actually made 8 layers…but more on that in a second.

When starting on the epic journey of making a multiple layer cake, keep in mind that even if it’s not ‘perfect’, everyone will be blown away by it anyway!

Rainbow cake

Pastel Confetti Rainbow Cake

I’m no artist, so achieving a shade I was happy with was trial and error.  Adding blue colouring to the yellowish cake batter makes a murky green colour, so the trick is to add a dab of violet colouring, and, hey presto, blue. First time round the blue didn’t seem to be very, well, blue. Naturally, I got impatient and sloshed too much gel paste in, resulting in a colour that was far too vivid for this cake! The first yellow layer came out wonky, so once again I started from scratch… little girl was in 7th heaven with her blue and yellow ‘calamity cake’!

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Time permitting, I probably would’ve made 10 layers (!), as I didn’t quite achieve the shade of blue or pink I was hoping for, but you’ve got to know when enough is enough – time to step away from the cake!

Don’t be alarmed if the cakes look brown when they come out of the oven, this is just the outside. Inside the beautiful colours will be revealed, I promise. I didn’t take any photos of the various stages this time, so have a look at this Rainbow Cake Tutorial by Finch bakery.

This cake needs a Himalayan MOUNTAIN of butter icing, like I said, not a cake for the faint hearted! If you prefer, you could sandwich the cake layers together with jam which would use about half the amount of icing.

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Personally, I like the contrast of white icing between the colourful layers, and I love that the white icing hides the rainbow inside, with the sprinkles acting as a tantalising hint as to what lies beneath. Imagine the reaction when the first slice is cut! I got the idea of the piped border with sprinkles from Sweetapolita, the queen of layer cakes. If you haven’t checked out her blog yet, you should swing by soon – the photos are a.m.a.z.i.n.g, such inspiration.

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I decided to put some dessicated coconut around the side of the cake, to add some texture and flavour – and, if I’m being honest, it was stressing me out that I couldn’t get the butter icing totally smooth. One of Lizzy’s housemates declared that the coconut ‘really made the cake’, so this turned out to be a great last minute addition, and also meant I didn’t have to spend hours smoothing the sides, bonus 🙂

Getting to Lizzy’s house with baby, cake and presents in tow was a bit of a mission, but so worth it to celebrate her birthday, and to hear the ooohs and aaaahs when the cake was finally cut open!

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‘That is insane’, ‘the coolest cake ever’, ‘totally awesome’ – I think I passed the student critique with flying pastel rainbow colours. Phew!

And Lizzy, you may not be a teenager anymore, but at least you know you’ll never be too old for fun-tastic cakes 🙂

Happy Birthday!

Ruth 🙂

P.S Lizzy also got some piping nozzles, a proper piping bag and a cupcake machine for her birthday – so there’ll be no more complaining about cupcake catastrophies due to the oven in her student digs or value freezer bags used for piping (but that’s a whole different story)! Watch this space to see how the cupcake machine works out…

Top Tips for making a coloured cake:

*Invest in some gel paste colours, you only need to use a bit, so even though they’re pricey, they last for ages and they don’t affect the flavour or consistency as much as liquid colours.

*The shade of the batter is pretty much the shade the cake will be, so don’t put it in the oven until you’re happy with the colour (if anything, I found the colours were slightly more vivid when you cut the cake open).

*To achieve a blue, you need to add a dab of violet to the blue, otherwise it’ll be green due to the buttery colour of the batter.

*For lilac/lavender add a touch of pink to violet.

*The standard pack of Wilton gel colours doesn’t include orange, so you can either buy it individually or mix red and yellow.

*Cream together the butter and sugar until it’s very pale – I find this helps to get a better shade as it makes the batter less yellow.

*Have a prop to copy the shades you want – I used the confetti sprinkles and the nail polishes.

*Don’t worry that the cakes look brown when you take them out of the oven, this is just the outside – inside will be the colour.

*Make the cakes as level as possible before putting them in the oven.

*Digital scales make measuring out easier. Weigh out the whole batter, divide and separate into bowls, so that each layer is the same thickness.

*And remember, even if it doesn’t turn out perfect, everyone will love it anyway! 🙂

To make this cake, you will need:

2 x 8 inch / 20 cm cake tins

Greaseproof paper

Weighing scales (digital scales are best for total accuracy)


Bowl & Wooden spoon OR electric mixer

Measuring spoons

Lots of bowls

Piping bag and star nozzle (if you want to do a piped border)

Plenty of time and patience

Cake Ingredients:

350g soft margarine, or very soft butter

350g caster sugar

6 large eggs

350g self-raising flour

2 tsp baking powder

2 tsp vanilla extract

Gel food colours

Sweetened dessicated coconut (if you want to put coconut round the sides, like I did)

Butter Icing Ingredients

400g unsalted butter, at room temperature

800g sifted icing sugar

4 tbsp milk

1 – 2 tsp vanilla extract

See basic butter icing recipe for the method.

All-in-one method (slightly adapted):

1. Preheat the oven to 170 degrees fan (or the temperature you use to bake cakes in your oven, each oven is different)

2. Prepare 2  8 inch / 20 cm cake tins (more if you have them) with a disc of greaseproof paper in the bottom. Make sure you butter the bottom of the tin to get your greaseproof disc totally flat. The cake layers are very thin, so creases in the greaseproof paper will matter!

3. Cream together the margarine and caster sugar until light and fluffy. This is an important stage, it helps to make the batter less yellow which means it’s easier to get the shade you want at the colouring stage.

4. Add the lightly beaten eggs and sift the flour and baking powder into the bowl. Add the vanilla.

5. Now beat everything together briefly until everything is only just incorporated. You don’t want to overbeat at this stage -overbeating the flour makes the cake crumb less tender. You are still going to have to stir in the colour, so bear this in mind.

6. Weigh ALL the batter, then divide this amount by 6. This is the amount you need to weigh into 6 separate bowls (perfectionist, moi?). It might seem like a faff, but this is the best way to make sure all the layers are even, so it is worth it for the end result, trust me.

7. Add a little of the colour to each batter until you are happy with the shade. Try not to overbeat. The colours do loosen the batter.

8. Put the cake batter into the tin and use the back of a spoon to make sure the batter is as level as possible. Take some time over this.

9. Bake for between 12 – 14 minutes. The cake should spring back when lightly touched and a skewer should come out clean. They are quite thin layers, so be careful not to over bake.

10. Leave in the cake tin to cool for a couple of minutes, then remove and leave to cool on a baking rack.

11. Once cooled, level off the tops of the cakes with a knife, if they are domed.

12. Make the butter icing and stack the cakes one on top of the other, putting a thin layer of icing between each layer. Remember to start with the colour you want at the bottom.

13. Crumb coat the top and outside of the cake and pop in the fridge for a couple of hours. A crumb coat does just what it suggests, a very thin layer of butter icing which acts as a seal for all the crumbs, so that when you  put your final, thicker layer of icing on the cake no colourful crumbs will get mixed up in it!

14. Ice the tops and sides of the cake with a thicker layer of butter icing, on top of the crumb coating. Pat the coconut on the sides and pipe the border if you fancy.

15. Go sprinkle crazy

The baking world has been going rainbow crazy! Take a peek at these rainbow cakes for more inspiration:

5 thoughts on “Pastel Confetti Rainbow Cake

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