Rainbow Cake

Rainbow Cake
Rainbow Cake

This cake is similar to my Rainbow Layer Cake. Full instructions for making the Rainbow Layer Cake can be found here.

A slice of Rainbow Cake
A slice of Rainbow Layer Cake

I made this cake for Linda’s birthday.  Her husband secretly ordered it from me and I thought that such a romantic gesture wouldn’t be complete without some love hearts!

It really is as simple to make as the photos look – you dye the cake batter, pour into the pans and bake!

It is based on a white mud cake, filled with white chocolate ganache and covered in sugar paste
This cake was so much fun to make and eat!  I love the surprised look on peoples faces when you pull out the first slice ~ Rainbow cake is something that makes everyone smile 🙂
If you need more information on how to make ganache and cover your cake with it just click here.

Two things make this cake special

1. The Rainbow Inside. A really big surprise if the recipient and/or guests have no idea what is inside.

2. The cake is based on a White Chocolate Mud Cake. Lots of people are scarred to use colours with Chocolate mud cakes if they do not have the special chocolate colours. I did a lot of research before I used my ordinary food colours and the reason they work is because we are not colouring 100% pure chocolate. The other ingredients magically make it alright to use Wilton or AmeriColor (these are the only two makes that I have tried so far).

7″ White Chocolate Mud Cake (Planet Cake recipe)

I used 2 x 7″ pans
180g butter
180g white chocolate
160ml water
195g SR flour
180g plain flour
240g caster sugar
2 eggs, lightly beaten
1 tsp vanilla essence


780g white chocolate, finely chopped
270g pure cream

730g yellow sugar paste

small amounts of orange, red, purple, blue and green sugar paste
White Chocolate Mud Cake Method

    1. Preheat the oven to 180C.
    2. Grease and line bases of both cake pans with baking paper.
    3. Combine chopped butter and water in a saucepan.
    4. Stir over low heat until butter is melted. Turn off heat, then add the chocolate and stir until it has melted and is well combined.
    5. Sift flours into a bowl. Add sugar, a pinch of salt and make a well in the centre.
    6. Pour chocolate mixture, egg and vanilla into the well then stir with a wooden spoon until well combined.
    7. Divide the batter equally amongst the 6 bowls. Weigh your mixing bowl before you begin adding ingredients and then subtract the weight of the bowl from the final measurement after the batter is completed. Divide that number by six and add that weight of batter to each bowl, and then whisk a fair amount of the appropriate food colour into each bowl. Keep in mind that the color of the unbaked batter will be the color of the baked batter.
    8. I poured 5/6th of the red batter into the pan that would be the top tier. I spread it out a little to touch the sides of the pan and be a little thinner in the middle.
    9. I then poured 4/6th of the orange batter in the middle of the pan on top of the red. I moved it about a little to make a good circle.
    10. I then poured 3/6th (i.e. 1/2) of the yellow batter on top followed by the green, blue then purple.
    11. In the second pan that would be the bottom tier, I first of all poured 5/6th of the purple batter followed by the blue, green, yellow, orange and finally red.
    12. Bake for 30 -35 minutes or until a skewer comes out clean when poked into the middle of the cakes.
    13. Leave in tins to cool completely on a wire rack.
    14. When cool, cut the domes off both cake and sandwich together with white ganache making sure that the bottom tier is placed upside down to create the design in my picture at the top of this post.

White Ganache

1. Place chocolate pieces in a large bowl.
2. Put the cream in a saucepan and bring to boiling point. Pour the cream over the chopped chocolate and mix with a hand whisk until the ganache is smooth.
3. Allow to cool completely and then leave to set overnight, if possible.

Colours of the rainbow
Colours of the rainbow
Coloured cake batter
Coloured cake batter
Ready for the oven
Ready for the oven
Cooling on a wire rack
Cooling on a wire rack
Rainbow Cake
Rainbow Cake
Rainbow Cake
Rainbow Cake
Rainbow Cake
Rainbow Cake
Rainbow Cake
Rainbow Cake
Rainbow Cake
Rainbow Cake

Retro Birthday Cake

This stunning 8″ round cake is a Vanilla Buttermilk Cake layered with Swiss Lemon Meringue Buttercream and covered in sugar-paste.
One thing I really like about this particular buttermilk cake is that it is essentially a one bowl cake, not following the regular cake pattern of creamed butter and sugar, eggs added one by one and then alternating dry and wet ingredients. That’s the good part. The bad part is that it is imperative that you scrape down the bowl often, all the way to the bottom, overdoing it even. Otherwise, little deposits of unmixed butter or flour will sneak up on you.
Otherwise, the cake is really quite simple.
Vanilla Buttermilk Cake 8’ round / 7’ square cake
700 ml cake flour
 (replace 6 tbsp plain flour with corn flour) explained below
470 ml sugar
4.5 teaspoons baking powder
0.4 teaspoon salt
230 g unsalted butter, at room temperature
245 ml plus 60ml buttermilk
4 whole eggs
2 egg yolks
2 teaspoons vanilla extract
1. Preheat the oven to 160C / 325°F. Butter an 8-inch round cake tin. Line the bottom of the pan with a round of parchment or waxed paper and butter the paper.
2. Combine the cake flour, sugar, baking powder, and salt in a large mixer bowl. With the mixer on low speed, blend for 30 seconds. Add the butter and 245 ml of the buttermilk. Mix on low speed briefly to blend; then raise the speed to medium and beat until light and fluffy, 2 to 3 minutes.
3. In a smaller bowl, whisk together the whole eggs, egg yolks, vanilla, and the remaining 60 ml buttermilk until well blended. Pour one-third of the egg mixture into the cake batter at a time, folding it in completely after each addition.
4. Bake for 2 hours, or until a wooden toothpick inserted in the center comes out clean.
5. Turn the cake out onto a wire rack by placing a rack on top of the pan, inverting it, and lifting off the pan. Peel off the paper liner and let cool completely. When cool, place a cardboard cake board on top of the cake, invert again, and lift off the rack. Wrap the cake on its board completely in plastic, so it doesn’t dry out, and refrigerate.
What is Cake Flour?
Replace 2 Tablespoons per cup (per 240ml) of all purpose flour (plain flour) with cornstarch (corn flour) to reduce the gluten content without sacrificing volume.
Recipes that call specifically for cake flour should have liquid volumes calibrated accordingly, so the won’t turn out dry, as long as you don’t ADD the corn flour, but incorporate it, so that the dry volume is the same.
Commercial cake flour is also finer than regular flour. Sifting a few times through with the cornstarch or zipping through a food processor can really help when you’re trying for a lighter-textured cake. “All-purpose flour” seems to be labeled “plain flour” in Australia.

Swiss Lemon Meringue Buttercream

This all-purpose buttercream has an ultra-silky, stable texture that spreads beautifully over cakes and cupcakes, and can be piped into perfect peaks and patterns.
The recipe makes enough to fill a 3 layered 8″ cake or for 24 (or 18 if piping a tall topping)  cupcakes.


4 large egg whites
250g Caster Sugar
pinch of salt
250g Unsalted butter/ softened
1.5 lemons, zest only


Combine egg whites, sugar, and salt in the heatproof bowl of a standing mixer set over a pan of simmering water. Whisk constantly by hand until mixture is warm to the touch and sugar has dissolved (the mixture should feel completely smooth when rubbed between your fingertips).
Attach the bowl to the mixer fitted with the whisk attachment. Starting on low and gradually increasing to medium-high speed, whisk until stiff (but not dry) peaks form. Continue mixing until the mixture is fluffy and glossy, and completely cool (test by touching the bottom of the bowl), about 10 minutes.
With mixer on medium-low speed, add the butter a few tablespoons at a time, mixing well after each addition. Once all butter has been added, whisk in lemon zest and a little yellow food colouring gel (optional). Switch to the paddle attachment, and continue beating on low speed until all air bubbles are eliminated, about 2 minutes. Scrape down sides of bowl with a flexible spatula, and continue beating until the frosting is completely smooth. Keep buttercream at room temperature if using the same day, or transfer to an airtight container and refrigerate up to 3 days or freeze up to 1 month. Before using, bring to room temperature and beat with paddle attachment on low speed until smooth again, about 5 minutes

Once the cake is layered with the buttercream it needs a crumb coat. Swiss Meringue Buttercream is not much use for this as it is quite soft. On this occassion I have added a very thin coating of white chocolate ganache but could have used a crusting decorators buttercream instead.
This nice firm crumb coat will make it easy to get a nice finnish on the sugar paste covering.

Brush the cake with a thin layer of water (boiled and cooled) this will help the sugar paste stick to the cake.
I used just under 1 kilo of white sugar paste to cover the cake and coloured a further 200g pink, 200g orange and 200g yellow.
I used a pizza cutter to cut out Paisley pattern teardrops, triangles, long ovals, circles and flowers then randomly placed them all over the cake. I stuck them down with some edible glue but a little water would have worked just as well.
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