Jazz up a simple cake and add an element of fun with this rainbow cake topper tutorial. It’s easy, colourful and suitable for all levels of cake decorators.
My buddy Cherrie asked if I’d like to make a rainbow cake topper for her little girl Ashley’s 3rd birthday cake. Since Ashley is a big fan of My Little Pony, she was making a pink cake and would top it with the rainbow cake topper and a My Little Pony toy. The plan was to pop over to her place and help make the buttercream icing and decorate the cake. I don’t get the opportunity to make pretty pink cakes very often, so I jumped at the chance to help!
I’m a massive fan of 2D cake toppers that stand up (check out my ruffle heart cake topper tutorial here) because they really help a cake ‘pop’. Rather than having a cake topper that lies flat on top of a cake, I think these add so much more visual impact. This is such a fun and colourful cake topper so we want to show it off to its full advantage!
This topper will need a couple of days to dry, so give yourself some time to plan ahead. My collection of gel colours is a mish mash of different brands so feel free to use the colours you have on hand. If you’ve got a fondant extruder, you can use that to create the rainbow if you like.
I used a 6cm circle cutter to mould the rainbow and the finished rainbow just fit on a 5″ round cake. If you’re making a smaller cake, or if you have other decorations to go on the cake (like buttercream swirls for example), use a smaller cutter to give you more room around the rainbow.
For this rainbow cake topper, you will need:
Orange Fondant (I used Americolor Orange)
Rainbow cake topper tutorial
Let’s get started!
Work out the order of the colours for your rainbow. I decided on pink at the top, then purple, blue, orange and green.
We’ll start with the green first. Push your ball of green fondant into the tylose/CMC powder. Mix in the powder that sticks to the fondant. Create a long sausage of fondant and use the fondant smoother to roll over the sausage which will ensure it’s even and smooth.
Mould the green sausage around the circle cutter. Make sure it’s a snug fit around the cutter. Trim off each end of the rainbow – mine is about half way around the circle.
Repeat the above process with the orange fondant – this time though add a thin layer of sugar glue around the top of the green fondant and then mould the orange fondant over the top. That will ensure the two rainbow layers stick together. For the green and orange layers of the rainbow, we’re not going to curl up the ends – that will begin with the next colour.
Next take the blue fondant and mix in the tylose/cmc powder. Create a long sausage on fondant, give it a going over with the smoother and taper one end so it comes to a bit of a point. Brush some sugar glue along the top of the orange fondant and mould the blue fondant over the top. With the tapered, pointy end, start to coil it up so it creates a swirl.
If you find the fondant starts to crack when you’re making the swirl, you can add a little vegetable shortening (like Crisco) to soften it or add in a tiny bit of fresh fondant (with no added tylose/cmc powder).
Repeat the above process with the purple fondant, creating the swirl above the blue fondant and securing in place with sugar glue.
Repeat again with the last colour, pink.
To make the rainbow stand up on the cake, we’ll insert a couple of toothpicks in the bottom – these toothpicks will go directly into the cake.
Gently place your fingers over the left side of the rainbow. Your fingers will hold it all in place while you’re inserting the toothpick. Take the toothpick and dip the end into the sugar glue. Insert that end into the orange fondant – or whatever colour you have in that position – approximately half way up the toothpick. Repeat with the right side of the rainbow. Now your rainbow should look something like this….
I removed the circle cutter while the topper was drying – that way air could get to the green layer. Once you feel like the front is totally dry, you can gently flip it over so the back completely dries too. To make the clouds
Take some white fondant and push it into the tylose/cmc powder. Mix in the powder that sticks to it. Roll it into a sausage and taper both ends into a point.
Take one end and start to coil it around a little. Take the other end and coil it around in the opposite direction (as shown below).
Use the Dresden tool to make a couple of lines along the clouds which indicate the wind.
Repeat the above process to create a second cloud. Stand the clouds upright and gently push them into your work surface a little – this will help make the base of the cloud flat and stand up better on the cake. You can also insert a toothpick into the bottom of each cloud which will help secure it to the cake. Pop them aside to dry.
Once the rainbow has had a chance to dry for a couple of days, it should stand up like this when inserted into the cake…
To add some stars and personalise the rainbow with a name and age…
First add some tylose/cmc powder to the yellow fondant and mix it in well. Use the Star plungers to create one medium sized star and a few smaller stars. Pop them aside to dry.
For the name and age I used the FMM Block Letter Tappits – they’re my favourite! You can of course use any letter cutters you have available. Although these are my favourite letter cutters, we have a bit of a love/hate relationship and a few cranky words have been spoken when trying to get these little suckers out. If you’ve used these before, I’m sure you can relate!
Add some tylose/cmc powder to the white fondant and mix it in well. Roll the fondant out into a long sausage and use the rolling pin to roll it super thin. If it’s too thick, it will make getting out of the letter mould more difficult. Leave the fondant strip to dry for about 15 minutes – you can flip it over so the back dries too.
Once dry, take the paintbrush and coat the inside of the letter with cornflour. Place the letter over the strip, push it down firmly and wiggle it about so the letter cuts through the fondant.
Flip it over and run your finger over the letter to remove any straggly bits of fondant. Now this is the fun (or not so fun!) part! If you give the tappits a good whack on the table, you might be able to remove the letters easily. If not, use the pin to gently remove the letter. TIP!
If the letter is falling apart and not coming out cleanly with the pin, leave the fondant strip to dry a little longer or place the letter cutters in the freezer for 10 mins to firm up the fondant.
Cut out all the appropriate letters for the name and age.
To attach the name, age and stars, I found it easier to lie the rainbow down flat on the work surface and arrange them in position on the rainbow. That way I could work out their placement before securing them with sugar glue. When you’re happy with the position of the stars, name and age, brush a little sugar glue on the back of each one and gently adhere it to the rainbow. Insert the rainbow on top of the cake and arrange the clouds in front. You should now be looking at a rainbow that looks similar to this….
For such an easy topper, it really packs a visual punch!
If you enjoyed this fondant rainbow cake topper tutorial, don’t forget to PIN it!