Psychedelic Rainbow Swirl Lollipop Cake

Woaaah. This cake is a bit of an attack on the eyeballs isn't it? But I love it so much. I think this may be my favourite cake that I've made this year. Yes, even more than the Pocky Cake. Last week was Regex Man's birthday, and in case you don't remember, he has been the recipient of some of my craziest cakes; the Mint Chocolate Chip Cake, the Rainbow Cake with jelly beans and the Fudge Brownie Cookie Dough Cake, just to name a few. He was also the inspiration behind my beloved Fruit Tingle Cake i.e. pretty much the best icing I have ever made. He has a sweet tooth that rivals my own, and I always feel like I can go super over the top on his cakes and he'll love it.

But this year I was completely out of ideas. I've been in a creative baking rut for a while now, and I keep having to force myself out of it. I looked to the internets for inspiration in my time of need. I came across this visually stunning but seriously simple decorating technique from Hungry Happenings and immediately loved it. I decided it would be a perfect idea for this cake since last year I put a rainbow inside the cake, and this time I would put a rainbow on the outside. I'm also a big fan of Katherine Sabbath (if you're not following her on instagram, you should be) and remembered her gorgeous lollipop-covered cake and realised that rainbow lollipops would be the perfect topper for this particular cake. This cake is exactly the type kind of cake I like to bake because it's so impressive looking but is actually relatively straight-forward to make. And there's rainbows and lollies and popping candy. I love how the swirling icing matches the lollipops so that it kinda looks like the lollipops are melting all over the cake.

I simplified the swirling rainbow decoration on the top of the cake by using royal icing instead of white chocolate ganache. It was less work, quicker to set and I think it helps ensure a brighter colour since you're working with a bright white icing as the base rather than a semi-translucent white chocolate ganache. I definitely suggest using gel colouring if you want to achieve the same brightness of colours in your royal icing. No innards shot of the cake, but it was fairly simple; a vanilla layer cake with Fruit Tingle Icing in between the layers and vanilla icing on the outside. Just so you know, I sat and ate the whole of that huge lollipop at the back while watching the Lego Movie. It was pretty great.

Psychedelic Rainbow Swirl Lollipop Cake

(makes a tall 3-layer 6" cake or a shorter 7" cake, icing idea adapted from this recipe)

For the cake:

355g (about 2.5 cups) plain/all-purpose flour

4 tsp baking powder

1/2 tsp salt

225ml (about 1 cup minus 1 tbsp) milk

2 tsp vanilla extract or scraped seeds from 2 vanilla bean pods

350g (about 1 & 3/4 cups) sugar (granulated or caster)

225g (2 sticks) butter, softened

4 eggs

1. Preheat oven to 180°C (350°F) and grease three 15cm (6 inch) (or 18cm (7 inch), cake will be shorter) round cake tins. Line the base of the tins with baking paper. 
2. Combine flour and baking powder in a medium bowl and set aside. Mix milk and vanilla together in a measuring jug.
3. Using an electric mixer on low speed, beat sugar and butter in a large bowl until blended. Increase speed to high and beat well until very pale and creamy, at least 5 minutes. 
4. Reduce speed to medium low, add eggs 1 at a time, beating well after each addition. 
5. Alternately add flour mix and milk mixture, beginning and ending with flour mixture (I did it by adding 1/4 of of the dry mixture followed by 1/3 of the wet mixture at a time). Beat until smooth, occasionally scraping bowl with a spatula. 
6. Split mixture equally between prepared tins and smooth top with a spatula (I usually do this accurately by weighing the batter first)
7. Bake until a skewer inserted into the centre just comes out clean and the outside is golden, about 35-40 minutes (will vary depending on your cake tin size). Take cake not to overbake or cake will be dry. 
8. Cool in tins for 15 minutes, then carefully turn out on to a wire rack to cool completely. Keep cakes wrapped in clingfilm and chilled in fridge until you are ready to assemble. Can be stored in an airtight container overnight if you want to prep the cakes a day ahead.

For the vanilla icing:

800g (about 6 1/2 cups) icing (powdered) sugar, sifted (or blitzed in the food processor)

400g (about 3.5 sticks) butter (I use salted, add about 1/2 tsp of salt if you use unsalted)

1 tsp pure vanilla extract

2- 4 tbsp milk adjusted to taste/consistency
Optional: 2-3 rolls of Fruit Tingles or any other fizzy tablet candies like Bottle Caps or Smarties (not the chocolate covered candy with the same name), SweeTarts or Barratt's Refreshers

1. Prepare the icing; remove butter from fridge 30 mins before starting and chop into small cubes. In a large mixing bowl, beat butter on high with an electric mixer until smooth and fluffy. 
2. Reduce speed to medium-low and gradually add icing sugar until combined, add vanilla then increase speed to high and beat until very pale and fluffy. 
3. Gradually add milk until you reach desired texture, you may need to add more icing sugar if your mixture is too runny, or more milk if you mixture is too stiff. The icing should be smooth and easily spreadable, but stiff enough to hold its shape.
4. Optional: Separate 1/3 of icing mixture in a separate mixing bowl. Place Fruit Tingles in a food processor and blitz until it breaks down to small crumb-sized pieces. Using an electric mixer, gradually beat fruit tingle pieces into the icing, adding to taste.
5. To assemble cake; remove cake layers from the fridge and use a long shape knife (preferably serrated) to carefully trim the tops of the cake to ensure they are level. Flip your cake layers upside down before assembling.
6. Place one layer on your cake stand and use an offset spatula to spread a thick layer of icing (I used the Fruit Tingle icing for the filling of this cake) over the top of the cake. Repeat with remaining cake and more icing.
7. Crumb coat cake and then chill for about half an hour, then cover with remaining icing (plain vanilla) and smooth with offset spatula.
8. Chill cake to set icing, and prepare royal rainbow icing below.

For the royal rainbow icing:

Note: can be replaced with storebought royal icing mixture if you prefer (like this)

1 large egg white (can be replaced with 2.5 tbsp meringue/eggwhite powder + 5 tbsp water)

2 cups (about 250g) sifted icing/confectioner's sugar

Juice from 1/2 lemon

Food colouring (I used Wilton gel colours to achieve a more vibrant colour without using too much colouring)
To decorate: rainbow lollipops in a variety of sizes and shapes

1. Place egg white in a medium mixing bowl and beat with an electric mixer to form soft peaks. 
2. Add icing sugar and lemon juice and stir with a spatula to combine. 
3. If icing is too thick, add water 1 tsp at a time; if it is too thin, add more icing sugar. You want your mixture to be a thick but still running paste, if it is too thin it will run right off the cake and if it is too thick it won't mix and drip down the sides.
4. Split mixture into 6-7 bowls and add colour to each bowl. I did yellow, orange, red, pink, purple, blue and green.
5. Carefully drizzle small amounts of each colour over the top of the cake. I started from the centre and worked my way out, this makes it easier to gauge when there is enough icing for it to just start over-flowing around the edge of the cake. Some of the icing may pool around the bottom of the cake stand, you can either leave it or attempt to wipe it up but it may get messy. (Another option is to place strips of baking paper around the edges of the cake so that it catches the excess without messing up your plate). This gif might help give you an idea of how it should look.
6. Chill cake until ready to serve, then remove from the fridge 30 minutes before serving and decorate with lollipops. I also decorated the bottom of the cake with some rainbow popping candy.