School Cake!
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A delicious and simple vanilla school cake with icing and sprinkles – the classic easy bake for everyone.

YES THAT IS RIGHT… THE RECIPE IS FINALLY HERE! School cake!! This, again is one of the most highly requested recipes to go on to my blog, and I thought it was about time… just in time for school starting again this year!
This cake is iconic – and one of the cakes that no matter how ‘plain’ it is – I will ALWAYS want to eat it. There is just something about it. It’s sweet, but delightful. If you haven’t heard of it… you must try school cake now!

Sponge
School cake, for those who don’t know… is a really very simple recipe. It’s a vanilla sponge cake, topped with water icing and sprinkles. It really is that simple. If you include the water as an ingredient for the icing, it is eight ingredients, but I don’t think thats too bad.
The cake is light and moist (if I can use that word…) with the vanilla flavour. You simply have to make a basic cake sponge. Theres something about the vanilla sponge and sprinkles together that tastes DELICIOUS however, if you wanted a chocolate version – follow this recipe here.
- Butter – for the sponge mix, you can use a block butter at room temperature, or a baking spread – both work well
- Sugar – I use caster sugar as it’s a basic cake mix, and you want the classic flavour from the sugar
- Eggs – the best method is to weigh the eggs in their shells. You want to get the weight to as close to 400g as possible, and then ideally match the sugar, flour and butter to match this weight for the best bake
- Flour – self raising flour is the best and classic. You can make your own by mixing in 2 level tsps of baking powder per 150g of plain flour, and mixing in before using
- Vanilla – this is optional, but I love the flavour it gives


Egg weighing method
So as mentioned above in the sponge section, weighing eggs is a useful method for cakes like this. I have listed 7-8 eggs, as eggs can vary in weight. I typically use medium eggs in the UK when baking, and these general range in size so they’re not always identical. I often buy mixed weight boxes as well so these can vary from 43-73g usually.
The best tip, is to weigh your eggs in the shells, to get as close to 400g as possible. Say the eggs weigh 411g, you then need to use 411g butter, sugar and self raising flour. The equal ratios create the perfect simple sponge that will bake wonderfully and it’s very hard to get wrong! The vanilla extract is optional, but I LOVE it.


Making the cake
To get the perfect bake, you really need to make sure you mix the ingredients properly. I use my stand mixer, but an electric hand mixer works, or even a bowl and spoon. Make sure if you use unsalted block butter that it’s at room temp, but baking spread can be fridge cold.
Beat the butter and sugar together until creamed, light and fluffy. It’s important to make sure you do this first in my eyes, compared to the all in one method, as it’ll make sure you don’t have any butter lumps. I then add in all the eggs, self raising flour and vanilla and mix again. If mixing with a bowl and spoon, you may want to add these a smidge slower so you don’t get in a complete mess, but otherwise mix until you see it’s combined and stop mixing.

Traybake tin and baking
I use a 9×13″ traybake tin to make this school cake, as I use it for all my traybake cakes. I love my chocolate traybake cake, my gin and tonic traybake cake and so on… but this one?! This school cake may be my favourite of all my traybake cakes.
If you aren’t sure on your oven, I always recommend using an oven thermometer so it bakes correctly! An oven I once had to use was 50ºc out! Absolutely awful for baking. After your oven is correctly heated, you want to bake the cake until a skewer comes out clean, and its not making a bubbling/crackling sound when you listen carefully.
If you cake sinks after coming out the oven, it needed longer baking. It really is that simple! It’s still going to be edible, so don’t be disheartened. Baking is all about learning the science behind it.


Decoration
Once the school cake is cooled, you can make the icing. It really is as simple as mixing water into the icing sugar, pouring it over the cake evenly, and sprinkling on some sprinkles! It’s as simple as it can get. I use these sprinkles as they are beautiful, bright and fun! They are 1000% bake stable and UK legal.
I use a basic icing sugar and water mixture for my icing, and it’s so simple. Add a little water at a time, and give it a really really good mix before adding more as you don’t want to make it too thin. Some people like to use milk in the icing, but this does mean the cake needs to be stored in the fridge as the milk is a fresh product, and this will dry the cake out, so water is best.
The most painful part is waiting for the icing to set a bit so it doesn’t pour everywhere – but it is worth it! This school cake is one of the best bakes ever, and I really hope you love it.

Making a smaller version
This tin is obviously quite large and I love making the traybake sized version as I would personally call it the ‘classic’, however I know not all of you want to make a cake that big.
So to make a smaller 9″ square version, you need to use: 250g unsalted butter, 250g caster sugar, 250g self raising flour, 5 medium eggs and a dash of vanilla extract. Bake into a lined 9″ square tin for around 35 minutes. Leave to cool fully, and then decorate. For the decoration on a smaller cake, I would use about 350g of icing sugar and 3-4tbsp of water for the icing.
Tips & Tricks
- I use these sprinkles in my decoration
- I use this cake tin for my traybake tins
- This cake will last 3-4+ days at room temperature
- This can freeze for 3+ months


School Cake!
Ingredients
Cake
- 400 g unsalted butter
- 400 g caster sugar
- 7-8 medium eggs
- 400 g self raising flour
- 1 tsp vanilla extract
Icing
- 500 g icing sugar
- 4-5 tbsp water
Sprinkles
- Rainbow sprinkles
Instructions
For the Cake
- Preheat your oven to 180ºC/160ºC fan and line a 9x13" traybake tin with parchment paper.
- Beat together your butter and sugar until light and fluffy.
- Add in the eggs, self raising flour, and vanilla extract and beat again until combined well.
- Pour into the tin and bake in the oven for 45-50 minutes, or until baked through.
- Once baked, let the cake cool fully in the tin.
For the Icing
- Add the icing sugar to a medium sized bowl, and gradually add the water, mixing well each time, until a thick icing paste is made.
- Carefully spread the icing over the cake evenly.
Sprinkles
- Sprinkle over your favourite rainbow sprinkles!
- Leave the icing to set for about an hour, and enjoy.
Notes
- I recommend using a 9x13" traybake tin for this recipe.
- This cake will last for 3-4 days once made.
- For a 9" square tin - I would recommend a 5 egg/250g sugar/butter/flour mixture. Baked for 35 minute - see more notes in the post
- You can use any sprinkles you like, but I use these sprinkles!
ENJOY!
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J x
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If I replace the eggs for aquafaba would it be 3 tablespoons per egg measurement? I will also be using dairy free margarine.
Hi can the school cake be frozen?
Loving the recipe 🙂
Yes absolutely you can freeze this for up to 3 months! Enjoy! x
Hi!
If I’m using 8×12 inch tin do I need to change quantities slightly or just bake it for a bit longer (and how much longer roughly?)
Thank you in advance!
Absolutely love this recipe. Such an old time fave in this house! So easy to make and fun for little ones adding all the sprinkles!!!
Hey Jane, what’s the best way to add the icing so it cuts neatly instead of running down the sides after being cut ?
Hiya! Try adding slightly less water to your icing so it is slightly thicker and therefore hopefully won’t run. Enjoy! x
Would the 9×12 tin work for this too with no adjustments?
Thank you
Made this with my little one this morning and we absolutely love it! so delicious- thanks for sharing the recipe!
Hi Jane,
Can you use large eggs in this recipe? If so would that change the weight of the other ingredients in the cake.
Thanks
Hiya! Yes, use 6-7 Large eggs, everything else will stay the same. Enjoy! x
Can this be frozen ok
Could I use a 10″ by 10″ tin without altering the ingredients? xx
Hello.
I am wanting to use this recipe to make a Spongebob Cake for my daughter’s birthday. Can I make two cakes and stack them, or will it be too big and fall apart?
Just made this but halved the recipe (because I didn’t check if I had enough ingredients! Woops!) And baked for 20 minutes and it is honestly the BEST sponge I have ever baked. So soft and spongey, will definitely make again!
Hi Jane, congrats on the book, my colleagues got it for me and I’ve already made a few bakes from it, all yummy! I’ve just made the school tray bake and decorating it in a Halloween theme for the grandchildren . My daughter made it a while back and said it’s the best cake ever so I thought I’d have a go too. Yes, it’s fab!
Could I put a food colouring into the mixture my grandchildren love this cake so was going to do a Halloween theme on top thanks
Yes you can! Just make sure to use good quality colours!
This sounds amazing. How can I make it gluten free please. Itll be my first attempt of a GF cake. Thank you
Love this recipe! Could I use dairy free butter and the same ingredients for a dairy free version?
Amazing cake! Only made half what the recipe said (as we didn’t need it so big ) and cooker for less time and it Turned out perfect!
Made this cake for my family , they said it’s the
Best evwr cake . I added a little butter to the
Icing , WOW made a difference soooò yummy