How To Make A Mermaid Cake That Will Guarantee A Magical Birthday!

Magical mermaid cake, with sea icing decorations and a mermaid tail sticking out the top.

Image © RuthBlack.

We know too well about the fascination of the mythical mermaid, with our under 10s as well as our tween daughters being obsessed.

With mermaid cakes offering an array of rainbow colours throughout, mermaid cakes always make pretty birthday cakes which your kids will love. The idea of making a birthday cake may seem daunting but with so many easy birthday cake recipes on offer, we can help you to come up with some fab mermaid cake ideas. If you're interested in learning how to make mermaid cakes or mermaid cake designs, this cake tutorial is for you.


For The Cake:

200g butter

200g caster sugar

4 eggs

1 tsp of vanilla extract

200g self-raising flour

Gel food colouring in blue

For The Buttercream Frosting:

500g of icing sugar

250g butter

1/2 tsp vanilla extract

Gel colouring in purple and blue

White chocolate to create your shells and other decorations


2 circular 20cm cake tins


Greaseproof paper (or you can use butter to grease the cake tins

A cooling rack

Moulds to create the decorations, (these can be found online or in a craft shop)

Table with a birthday cake covered in sprinkles, paper plates and party hats and colourful birthday decorations on it.
Image © Lidya Nada on Unsplash.


We are excited to help you with creating this easy mermaid cake. As this is one of the best birthday cake recipes suitable for any mermaid.

1) Preheat your oven to 180°C (160°C fan or gas mark 5) and grease your cake tins using butter or line them greaseproof paper. Weigh out all of your ingredients for your cake.

2) Making the decorations before the cake is useful as they can take a while to set, to do this you need to melt your chocolate in the microwave for 1 minute or so until it is liquid, then add colouring. When working with chocolate, you need to be quick, so the process of adding the dye and then pouring into moulds is time-sensitive. You can also make a mermaid tail out of fondant icing you can attempt this freehand or via a mould.

3) Pour the sugar and butter into a bowl and whisk using a wooden spoon or a stand mixer until smooth.

4) Crack the eggs into a bowl and beat until runny. Then tip them into the sugar and butter mixture gradually whilst stirring. Carefully pour in your 1/2 tsp of vanilla extract and whisk. Next, you need to sift the flour into your mixture, if possible, use a sieve when doing so to remove any lumps of flour.

5) Before adding the mixture into the tins, you can choose to dye your sponges if you like. Dependent on the theme of the cake you could aim for a cool blue which looks excellent as water or a deep purple, have fun with this. Whether you're looking to colour the whole sponge or add sections of colour, the choice is yours.

6) Evenly spread the mixture between the two tins then put in the oven for 25-30 minutes.

The best way to figure out if your cake ready is to take it out of the oven and use a fork or metal skewer to poke in the cake. If it comes out clean, the cake is ready to come out.

7) Allow your cake to cool for a few minutes, before removing the cake from the tins, then pop on to a cooling rack and leave until completely cool.

8) Once your cakes have cooled down, it's time to make the buttercream icing. To make this, you need to add together your icing sugar, butter, colourings and flavours then whisk. But make sure not to over whisk it as it is easily done. If you find your buttercream is grainy you will need to start over.

9) Place your two cakes side by side, and using a knife, evenly cover them with buttercream, if you're adding any other fillings such as jam, this is the perfect time to add this too. Then sandwich the cakes together.

10) Before using the decorations on your homemade birthday cake, you need to cover the outside with a layer of buttercream you can do this with a knife or a piping bag. Finally, add your decorations and some pearls and you're done!

Tips And Recommendations:

1) Looking for alternative mermaid cake recipes? You can choose to follow this recipe and make it more of an Ariel birthday cake or even just a little mermaid cake. By adding cardboard cutouts or buying decorations online, you can still make an Ariel cake whilst creating easy birthday cake ideas.

2) You can always use cupcakes instead of making a mermaid birthday cake- the same cake tutorial can be changed to fit cupcakes by splitting the mixture up into 12 cases.

3) For storage of your cake, you can cover with cling film and put it in the fridge, so your buttercream icing doesn't melt. Or, if you want to save some of your cake for later, why not freeze it? Wrap it up in clingfilm, then pop it into a freezer bag, removing as much as air possible and then freeze it. To defrost it, take it out and pop it on a plate and wait for it to defrost.

4) For a vegan cake/dairy-free use vegan alternatives such as vegan butter, and there are plenty of egg alternatives on the market which work the same way to bind the cake together. Make your decorations with vegan chocolate.

5) Other homemade birthday cake ideas including creating a mermaid tail cake, these involve a particular mould to create the shape of the tail.

6) The mermaid cake decorations can be as simple as you like, if you're looking to keep it easy you can add your own cardboard DIY decorations.



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