How To Get My Birthday Cake Recipe To Fit Your Tin and Other FAQs

One post on my blog that’s always popular is my all-in-one vanilla sponge birthday cake. It’s the recipe I use for almost all of my family’s birthday cakes and I absolutely love the idea that people are making and enjoying this on their family birthdays too.

However, it seems that popularity comes with lots of questions and I’m finding similar ones coming up again and again. People have told me that they’ve been scrolling through the comments to see if I’ve answered the questions before but with over 125 comments and counting it cannot be easy to spot the answer you’re looking for in amongst everything else. To try and help you all out I thought I’d pull together a quick post to answer all of your birthday cake FAQs as best I can and of course if I find new questions popping up in future I’ll add them in here.

birthday cake faqs title

Birthday Cake FAQs

Simply click on the question to jump to the right section

Can I make this cake in a different size and what quantities do I need?
Can this recipe be used to make cupcakes?
Can this cake be used to make tiers?
How far in advance can you make the cake?
Can you freeze the cake?
Can I use butter instead of margarine?
Can I substitute plain flour for self-raising flour?
What size eggs should I use?
Can I make this cake gluten-free?

If you’ve got a question not answered here then please let me know in the comments and I’ll do my best to answer it.

Can I make this cake in a different size and what quantities do I need?

The most comment question I’m asked is how to calculate the quantities to make the cake in a different size. To help you I’ve built this handy little calculator (I’m quite proud of myself for getting this working actually 🙂 ). All you need to do is pop your tin size and the number of layers of sponge you want in your cake into the green boxes and it’ll tell you what you need. The first calculator is for a round tin and the second is for a square or rectangular tin.

I’ve also calculated the ingredients needed to coat the cake in a layer of buttercream (with buttercream in between the layers too).

You need to enter the tin size in centimetres, if you only know yours in inches, simply multiply it by 2.5.

NOTE – I’ve not tested the cake in all possible sizes (I don’t have all those different tins for a start) so cannot guarantee success, However, as long as you don’t stray too far away from the original size I expect it should still work well.

Round Tin

Square or Rectangular Tin

Can this recipe be used to make cupcakes?

Yes, you can find the recipe to make this cake as cupcakes here.

Can this cake be used to make tiers?

My parties are all pretty small so I’ve never needed a cake big enough to justify tiers. It is quite a soft, light sponge and so I would expect it to be fine for 2 tiers but personally I wouldn’t risk 3.

If you are planning on making two tiers remember to include some sort of support in the lower layer (strong straws or dowelling cut to the height of the cake, and also put the top tier onto a thin cake board the same size as the cake (this adds additional support and also stops the moisture from the sponge ruining the fondant on the bottom layer).

How far in advance can you make the cake?

I usually bake my cakes on a Thursday and decorate them on a Friday for a Saturday party. We only have small parties so there’s usually some leftovers which have always lasted for a few days after the party. Make sure you store it in an airtight container to keep it fresh and if the weather is particularly warm I’d suggest keeping it in the fridge.

Can you freeze the cake?

Yes, you can freeze the undecorated sponge. Simply wrap it in clingfilm or an airtight bag and pop it into the freezer. When you want to use it remove it from the freezer and then make sure it’s fully defrosted before decorating.

Can I use butter instead of margarine?

Yes, just make sure you take the butter out of the fridge a little before you want to start baking to allow it to soften.

Can I substitute plain flour for self-raising flour?

I’ve only ever used self-raising (as I’ve always got it in the cupboard). Nigella suggests you can substitute plain flour by simply adding an extra 2 tsp of baking powder for each 150g of flour used (so for my original recipe you’d need an additional 3 tsp of baking powder).

What size eggs should I use?

I use whatever I have in the fridge! Most of the time that’ll be large eggs but it works just as well using medium.

Can I make this cake gluten-free?

You should be fine to substitute the self-raising flour for a gluten-free self-raising flour. Also, double check that the brand of baking powder you’re using doesn’t contain gluten (some do, some don’t).


  1. Hi. How long would i cook the 12inch square cake & what temperature?

  2. Hi there, can I decorate the cakes with the buttercream and leave outside the fridge? Or does it need to be refrigerated? Thanks, Aline

    • Not totally sure if you’re supposed to, but I do (as they’re too big to fit in once decorated) and they’ve always been just fine.

  3. My Grandaughter has asked for a no. 4 cake for her birthday, frozen theme x help. Gonna make it in a rectangular tin then cut to shape. Do you recommend buttercream or ready to roll icing. I would also like to make really easy chards for ice. Please help!

    • Buttercream v ready-rolled icing is really up to what you prefer using. I like using ready-made fondant as it’s what I feel most confident using (although I have a layer of buttercream underneath as it helps to get the icing smooth and I actually prefer the flavour to fondant). If you’re making a frozen cake then you’d probably be better off with fondant as it’s a pure white colour whereas buttercream tends to be more yellow. I’ve not tried making ice shards before so I’m not too sure of the best way, there seems to be quite a few tutorials on You Tube (although many are american and therefore use some ingredients that we don’t have in the UK) so I’d suggest watching a few of those and seeing if you can spot one which looks straightforward.

  4. Can’t afford a pre trial and can’t afford a mistake as I am a pensioner so a bit stressed about forth coming great granddaughters My Little pony cake 10″ and 8″ would you be an absolute Star and give me ingredients????!!! Jokatrina

    • Hi Kokatrina, is that 2 tiers, one 10″ and one 8″ or a 10″x8″ rectangular cake? If it’s tiers, are they round or square? How many layers of sponge do you want in the cake?

  5. Hello Charlotte,
    What does 2 layers mean? Does it means that I have to divide the ingredients in two tins before I bake it, or does it mean that I can cut the sponge cake in two layers after baking it.


    • Personally I cook the cake in two tins. You can cook it in one deeper tin but it will take longer to cook so check it after 45 minutes rather than the 30 suggested in the original recipe.

  6. Hi Charlotte,

    I’m using two 10 nick sandwich tins, how long do I bake for?

    Thanks in advance.

  7. Hi Charlotte, I will be baking a cake for my sons 1st birthday. I have an 8 inch cake tin which is 4 inches in height. Using your recipe, will I cook two separate layers or cook one big one and half it?

    • You can do either but if you cook it in one big tin it’ll take longer in the oven so don’t check it until it’s been in for around 45 minutes.

  8. Hi Charlotte,

    I’m making a Santa face cake for my children. I will be using a 10″ heart shaped tin. Any tips on the recipe amount would be gratefully received. Will it be better to do one deep and cut in half or two separate ones and cooking times too.

    Thanks so much, Cheryl

    • Hi Cheryl. Do you know the volume of the tin? (you can check by filling it from measuring jugs). If you let me know that then I can help you with the quantities. Personally I always make two separates rather than one deep cake but this recipe does work for deep cakes too. If you go for the deep cake make sure you don’t check it until it’s been in the oven for 45 minutes.

  9. Hello what quantities would do I need for a 12inch round tin I can’t get the calculation thing to work on here and it would be for 2 layers
    Thank you

  10. How much quantity of ingredients would I need for a 12 inch square tin and a 8 inch square cake tins?

    • For the 12″ square tin…

      620g flour
      620g margarine
      620g sugar
      11 eggs
      5.5 tsp baking powder
      1/4 tsp vanilla extract
      5.5 tsp milk

      For the 8″ square cake…

      280g flour
      280g margarine
      280g sugar
      5 eggs
      2.5 tsp baking powder
      1/8 tsp vanilla extract
      2.5 tsp milk

  11. Emma Louise Dadley

    Hello I’m making a 14″ round cake with 2 layers sandwiched together what quantities would I need and how long do I bake each layer for.
    Thank you

    • 675g flour
      675g margerine
      675g sugar
      12 eggs
      2 tbsp baking powder
      1/4 tsp vanilla extract
      2 tbsp milk

      As the layers are the same depth as in the original recipe they should take about the same amount of time to cook.

  12. Hi Charlotte, I love your site and I did your choc cake for my son’s 5th birthday (Harry Potter spell cake!). I now need to do a cake for my other son’s 7th birthday (nerf gun cake) and I’m looking forward to making your all-in-one vanilla sponge. Thanks for the calculator! It’s invaluable as both cakes use an enormous rectangular tin!
    I just have one question. How many ‘drops’ of vanilla essence would you estimate are in a teaspoon? My vanilla bottle does not have a dropper so I’ll be using a teaspoon measurer.
    Many thanks and keep up the good work!

  13. Hi Charlotte, I’m baking a 12″ square tin and using the recipe you’ve mentioned on your site. Can you give me a guide as to oven position, temp and how long to cook?
    I’d be very grateful.

  14. Hi Charlotte, Im a complete novice and making a birthday cake for my son and have a rice paper cake topper for a round cake – is ready rolled or fondant icing best for using underneath this? I will put a thin layer of buttercream underneath. Is it best to refrigerate before applying the ready rolled or fondant? Thanks so much

    • If you’ve got time then chill the cake after adding the buttercream as this will create a nice firm base for the fondant to go on. You can use ready rolled although you may find it’s not rolled out quite large enough depending on the size of your cake so you make need to roll it a little thinner. I tend to buy the block of fondant and roll it out myself.

  15. Hi Charlotte… Could you please give me a recipe for a 6 inch square tin. I’ve used the recipe for an8 inch round tin and the cake was amazing

    • 170g self-raising flour
      170g soft margarine
      170g caster sugar
      3 eggs
      1.5 tsp baking powder
      5 drops vanilla extract
      1.5 tsp milk

  16. Hi charlotte. What would the measurements be for a 12in square tin? It’s just for one layer.

    • 340g self-raising flour
      340g caster sugar
      34g soft margarine
      6 eggs
      1 tbsp baking powder
      1/4 tsp vanilla extract
      1 tbsp milk

  17. Hi Charlotte,

    i am planning on making your cake using a x2 20cm tins. I have never attempted to bake before. do i just place one cooked sponge on top the other other, with a layer of buttercream and jam in between? (what jam is best to use?) also would it be possible to add a third layer of cake or would you not recommend? Thank you!

    • Yes you just pop one sponge of top of the other. I always put a layer of buttercream in the middle and sometimes jam. I tend to use whatever jam I have in the fridge, so usually strawberry or raspberry, but any would be fine. I often add a third layer and it works really well.

  18. Hi I’m making a two tier cake, 8 inch and 6 inch. What is the best recipe please?

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