Rainbow Marshmallow Cake


Rainbow marshmallows

3 cups granulated sugar

6 tbsp gelatine powder + 1 1/3 cup cold water

1 1/3 cup hot water

2 tsp vanilla extract

3 drops yellow food gel

3 drops green food gel

3 drops blue food gel

3 drops purple food gel

3 drops pink food gel

3 drops orange food gel



This recipe makes 1 batch of vanilla cake batter and serves 15 people.


430 g 15 oz plain (all-purpose) flour

265 g (91/2 oz) caster (superfine) sugar

3 teaspoons baking powder

1/2 teaspoon fine salt

125 g (41/2 oz/1/2 cup) unsalted butter, softened

2 large eggs

375 ml (12½ fl oz/11/2 cups) full-cream (whole) milk

125 ml (4 fl oz/1/2 cup) vegetable oil

2 tablespoons Greek yoghurt (or sour cream)

1 teaspoon vanilla extract or vanilla bean paste

2 cups confetti rainbow sprinkles



1 batch swiss meringue buttercream frosting

3 drops yellow food gel

3 drops green food gel

3 drops blue food gel

3 drops purple food gel

3 drops pink food gel

3 drops orange food gel



1 cup large rainbow confetti sprinkles

½ cup large rainbow confetti sprinkles

½ cup large rainbow confetti sprinkles


Makes 20

Level: Easy

Rainbow Marshmallows

Grease a 4cm deep, 20cm x 20cm baking tin slab pan. Line the base and sides with baking paper, allowing a 3cm overhang at both long ends.


Combine sugar and hot water in a saucepan over medium heat. Cook, stirring for 3 minutes or until sugar dissolves and syrup is clear.


Using a whisk or fork, combine gelatine and cold water in a jug. Pour this mixture into the hot syrup. Cook, stirring, for 2 to 3 minutes or until gelatine has dissolved and mixture is clear. Pour into bowl and set aside to cool to room temperature (about 30 minutes). If the gelatine sets, pop it in the microwave for 15 seconds to liquify again and allow to cool for 5 minutes.


Using a stand mixer, beat sugar and gelatine mixture on high for 6 to 10 minutes or until very thick. Add vanilla and food colouring to reach desired colour and beat for 1 minute.


For this next bit, you’ll need to work quickly, because the gelatine can set quickly.


Split the mixture into 6 different bowls. Add each food gel into each one and use an electric mixer to mix the colour in. If you find your marshmallow mixture is setting, microwave it for 10 seconds to help soften it.


As you pour each layer into the prepared pan, make sure it’s not set. It needs to be about the same consistency as cake batter. That’s why microwaving it might be a good idea to be able to reach that consistency. Begin by adding the purple, followed by the blue, green, yellow, orange and finish with the pink. Add some sprinkles on top before you add it to the fridge to set for 4 hours.


Once it’s set, lift it out of the cake tin and use a large knife to cut into squares. Please note: the marshmallows need to be put on the cake no longer than a couple hours before serving otherwise they will begin to dry out.



To prepare the frosting, split into 6 large mixing bowls. Add each separate food gel colour and mix using a hand mixer until well combined. Add each one into a piping bag and set aside.



Please note: to make the 6 layered cake in this recipe, you’ll need to make 2 batches of vanilla cake. All other recipes and measurements are enough to put the cake together and decorate it.


Preheat a fan-forced oven to 140C (280F) or 160C (320F) for a conventional oven. Spray three 8” cake tins with oil spray and line the bottom with baking paper. Set aside


Add the flour, sugar, baking powder and salt to a large mixing bowl and mix together using a hand mixer until well combined.


Next add the softened butter and mix on low speed until mixture reaches a crumbly sand like texture.


Add the eggs, milk, oil, Greek yogurt and vanilla extract. Mix on low speed until no dry ingredients are showing. Scrape down the bowl and mix for another 20 seconds.


Fill three 8” cake tins with batter. I find using an ice cream scoop to help me do this makes it easy to distribute the batter evenly so that everything bakes at the same time. Pour 1/3 of the sprinkles into each cake tin and mix into the batter.


Bake for 50-60 min or until a toothpick inserted comes out clean. If the pick comes out with wet batter, bake for a further 10 min at a time until fully baked. Allow the cakes to cool to room temperature inside the cake tins and then chill them in the fridge overnight. Chilling your cakes overnight makes them easier to trim and decorate. So I bake my cakes the day before I decorate them.


Allow the cakes to cool to room temperature in the tins, then chill them in the fridge overnight. Chilling your cakes overnight makes them easier to trim and decorate, so I always bake my cakes the day before I decorate them.


To trim your chilled cakes, use a cake leveller or large serrated knife to carefully trim the crust off the top of each cake before you trim each cake in half. You’ll end up with 6 layers of cake.


This cake is a lot easier to make than most other cakes, because you don’t need to crumb coat, chill, then add a final layer. Instead we’re going to fill the cake inside a tube that you’ll create using acetate. Acetate is a plastic sheet. You’ll need a piece measuring about 29cm in height and 70cm in length.


Place the plastic sheet inside an 8” cake tin. Use sticky tape to stick it to the cake tin. Also, take care to stick the two ends together so that it all stay together as you’re filling it. Do your best to make sure the plastic sheet stands straight and isn’t slanted. If it’s a little slanted, don’t worry, it will straighten out when you start filling it.


Place the first layer of cake in the plastic tube. Then pipe a layer of purple frosting. Gently tap the cake tin against your workbench and repeat with each coloured frosting in the order of the rainbow until you get to the final layer. Finish with the final layer of cake and the pink frosting on top. Chill the cake in the fridge for 5 hours. Overnight is best.


Take the cake out of the cake tin and cut the tape away from the cake to unwrap it from the acetate plastic.


Add large sprinkles down he bottom of the cake. If you find that the sprinkles won’t stick to the cake add a little bit of frosting behind the sprinkles to help them stick to the cake. Add medium from the bottom of the cake to about half way and then add the smaller sprinkles from the bottom of the cake to the top. This will help you get an Ombre of sprinkles effect.


Finish by adding the marshmallow squares on top.







STORAGE: store in an airtight container for up to 3 days (refrigerated and thawed 1 hour before serving).


HOW TO PREPARE YOUR CAKE TIN: For this recipe you’ll need at least one 8” cake tin but preferably three 8” cake tins. To prepare the tin, spray with oil spray. To prepare the baking paper use a pen to trace around the bottom of the cake tin on to the baking paper. Use scissors to cut slightly inside the circle you traced. Place the traced side down onto the baking tin with oil spray.


HAND MIXER: Can be made using a hand mixer (always mix on lowest speed) or a hand whisk. Take care not to over mix the batter.


OVEN TEMPERATURE: Each oven is different. Some are old, some are new. Some ovens can be hotter on the inside than the temp you set your oven at. If you find your cupcakes, cakes or macarons are browning or cracking, turn the oven temp down 10C. A handy trick is to get an oven thermometer which sits inside the oven and will give you an accurate temperature reading. They’re inexpensive and can be purchased online or at your local kitchen supply store. And always bake in the centre rack of the oven for best results!


BUTTER: Make sure the butter is very soft for the cake mixture. Theres two ways to do this. Microwave for 5 seconds at a time flipping the butter on each side until very soft (not melted). If you don’t have a microwave run a large bowl over hot water. Dry the bowl and place over the butter for 1 min. The heat from the bowl will create a warm enough environment to soften the butter.


BAKING TIME: This cake will typically bake on a lower temp and for a little longer than regular cake recipes. I find a low temperate and a slow bake results in flatter tops and caramelisation so that if the cake is coloured it doesn’t change colour and brown. After 50 minutes, stick a skewer into the centre of the cake, if it comes out with wet batter, bake for another 10 minutes until the skewer comes out with crumbs or completely clean.




Cake turn table/lazy susan

Large mixing bowls


Magic Whisk for wet ingredients

Kitchen Scales

Stand mixer (or hand mixer)

Wire rack

Frosting bag


Measuring spoons

8” cake tin

Ice cream scoop (optional)

Cake turn table

Cake scraper/bench scraper

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