The softest and fluffiest wobbly sponge cake. Originating in Taiwan this souffle castella is lightly sweetened with the perfect pillowy texture.
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One of the most satisfying things is baking a perfect sponge cake. When the cake is at the perfect height and the surface is perfectly smooth and crack free. This castella is the definition of a perfect sponge cake. You won't find a cake with a better texture than this! The cake itself is light in flavour and slightly sweet, and the texture is light, pillowy and souffle-like.
Originating in Taiwan, these cakes are usually baked as large 1 metre slabs, sliced into large rectangles straight out of the oven, and placed in boxes to be picked up by the long line of customers waiting outside the stores. The popularity of these cakes is never-ending, and there are almost always lines outside the stores.
Although souffle castella was popularised in Taiwan, the original castella is a cake developed in Japan after being introduced by the Portugese. A traditional Japanese sweet made from bread flour, eggs, sugar and mizuame, a type of sugar syrup which gives the cake a moist texture, Japanese castella is a denser and slightly gooier in texture with a darker crust. Instead of being baked on a large scale like the Taiwanese adaptation, Japanese castella is baked in a wooden square or rectangular mould and enjoyed the day after it is baked as it brings out a moister texture.
While both cakes may have the same name they have their own unique charms. I personally love the Taiwanese style because of its fluffy texture, but give this recipe a go and see what you think!
How to achieve a crack free cake
Sponge cakes are the kind of cake that seem relatively simple, but there are so many small areas where things can go wrong. Whether that be a sunken cake or cracked top follow these steps for the perfect castella!
Heat the milk and butter until just melted
Heating the milk and butter is one of the tricks to achieving a cotton soft sponge cake. This technique is called the 'cooked dough' method, and essentially breaks down the proteins in the flour so that less gluten is formed, creating a soft sponge.
However, when heating the milk and butter keep a close eye on it so it doesn't overheat. If the milk and butter is too hot it can overcook the dough, causing it to form a sticky paste. The butter should have just melted and the milk should be just steaming.
Use chilled eggs
Chilled eggs whip up to create a firmer, more stable meringue. The meringue forms the base of this cake, helping it rise while giving it it's fluffy texture, so it is essential to have a strong foundation. You can also add a pinch of cream of tartar to your egg whites once foamy to help strengthen the meringue.
Whip the egg whites to soft peaks
One of the most important tips to creating a crack free sponge cake is only whipping the egg whites to soft peaks. If the meringue is whipped to stiff peaks it can cause the cake to rise rapidly while baking, increasing the possibility of the top splitting.
Add the sugar when the egg whites are just foamy, and whip until a dense meringue
While the egg whites should be whipped to soft peaks it is important to ensure that the soft peaks are dense and stable. The best way to create a stable meringue is to add the sugar as soon as the egg whites are foamy and beat the egg whites on medium-low for a longer period of time. This gives time for the sugar to dissolve, and the proteins in the egg whites to form a stronger network. When you look at the meringue the air bubbles should be fine and the surface should be shiny.
Bake the cake in a hot water bath
Baking the cake in a hot water bath helps to even out the oven temperature and create the perfect moist environment for the cake to bake. It is important to even out the oven temperature, as fluctuations in heat can cause the sponge cake to crack. Extra moisture also prevents the surface of the cake from drying out and becoming more susceptible to splitting.
Make sure the water you use in the hot water bath is hot, but not boiling. Boiling water evaporates quicker and could leave your cake dry halfway through the baking process.
Frequently Asked Questions
Why did my cake crack?
There are a couple of reasons as to why your cake cracked.
- The meringue was whipped beyond soft peaks
- The meringue wasn't stable enough
- The oven temperature was too hot
- The water bath used was too hot/ there wasn't enough water in the waterbath
To troubleshoot these errors check out my "how to achieve a crack-free cake" section above!
Why did my cake deflate?
As the name suggests this cake is a souffle castella, and will deflate slightly after cooling, however not enough for it to be a significant problem. If your cake is deflating a lot it could be be due to a couple of factors:
- The meringue was overwhipped, causing it to rise more during the bake
- The cake was underbaked
How long does this last?
This cake is best enjoyed on the day it's made, but it can last up to 3 days in an airtight container in the fridge. Allow the cake to come to room temperature before consuming if eating from the fridge, or you can toast it in the oven or toaster!
How is this cake best enjoyed?
I personally love this cake when it is fresh out of the oven. At this stage the cake is warm, soft and at its fluffiest. However, when cooled the cake is equally as delicious. Try serving it with some whipped cream and fresh fruit for a delicious all round dessert!
Let's Get Baking
If you are looking for the most satisfying sponge cake look no further! Soft and pillowy sweet perfection.
If you make these make sure leave a comment and rating down below, I would love to know how it went. Also tag me on instagram @catherine.justdessertsau and hashtag #cattycakes so I can see and share your creations.
Follow me on facebook, pinterest, youtube and tiktok for more of my baking creations and updates! Until next time... happy baking!
Print📖 Recipe
Taiwanese Souffle Castella
The softest and fluffiest wobbly sponge cake. Originating in Taiwan this souffle castella is lightly sweetened with the perfect pillowy texture.
- Prep Time: 15 mins
- Cook Time: 75 minutes
- Total Time: 1 hour 30 minutes
- Yield: 8 x 8 inch cake 1x
- Category: Cake
- Method: Easy
- Cuisine: Taiwanese
Ingredients
- 130g Whole milk (½ cup 2 tsp)
- 130g Unsalted butter (½ cup 2 tsp)
- 120g All purpose flour (1 cup)
- 8 Egg yolks
- 1 tsp Vanilla extract
- 8 Egg whites
- 130g White sugar (⅔ cup)
Instructions
- Preheat the oven to 140C
- Combine the milk and butter in a small saucepan over medium heat and heat until the butter has melted and the milk is just steaming
- Sift the flour into a large bowl and pour over the hot milk and butter, mix until combined
- Add the egg yolks and mix until smooth and well combined
- In a large bowl add the egg whites and whisk until foamy
- Add the sugar and beat on medium-low until the meringue reaches soft to medium peaks
- Add ⅓ of the meringue to the yolk mixture and mix until well combined
- Add the lightened yolk mixture to the remaining meringue and gently use a whisk to fold the mixture until just combined
- Transfer the batter to the lined tin and place it in a larger baking tray filled with hot, but not boiling, water
- Bake for 75 minutes or until the cake springs back when touched
- Remove from the oven and enjoy warm!
Keywords: cake, sponge cake,. castella, kasutera, taiwanese, jiggly
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Hi Catherine. Happy new year!!!
It is funny but I wanted to make this cake for about a month now and I kept postponing it. Now, that you made it I will definitely give it a try. Is it possible to tell us how to turn it into a matcha version?
Hi Dimosthenis, Happy new year! I haven't tried making a matcha version, but I would replace 1 - 2 tbsp of the flour with matcha powder. Hope it turns out great!
Hi! Just wanted to let you know that I think the recipe needs a tweak. I went with the weight measurements so mine turned out great. But the butter should be 1/4c + 2 tbsp, not 1/2c. The recipe also states vanilla extract, but it doesn’t say when to put it in. I just stirred it in at the end.
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Hi Jackie, Thanks for picking that up! The vanilla should be added with the egg yolks, as for the butter weight it should be correct as I converted it via density 🙂
So, 1/2 cup butter equals 113 grams, 1 tablespoon butter equals approx 15 grams, and 1 teaspoon equals approx 5 grams. So, 1/2 cup (113 g) + 1 tablespoon butter (15 g) = 128 g, which is close enough to 130 g. But, yeah, weighing ingredients will always yield the best results!
Hello again. I just made a matcha version and I have to say that I am amazed. It turned out great. I did it in a 9x9x2 inch pan. The ingredients should be:
150 gr Milk
150 gr Butter
127 gr Flour
10 gr matcha
9 egg yolks
9 egg whites
4.6 gr vanilla extract
150 gr White Sugar
For non-matcha just use 137 gr flour.
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Hi Dimosthenis, that sounds delicious, thanks for posting it! I was going to upload a matcha version soon too 🙂
I am so sorry if I spoiled a future recipe :(. I will also try a Durian flavor next week 😀
Not at all! In fact it's probably better since you've done some testing already 🙂 Durian sounds delicious!
Hi, thank you for the recipe. I made this cake and it was absolutely delicious but a tad sweet for me. Do you think it’s possible to change to brown sugar?
I also had a couple of things I want to ask. How did you get that nice brown top? Im getting a lot of cake bubbles with the final mixtures and I don’t know if it’s because I’m beating it at too high speed with the electric mixture.
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Hi! I wouldn't use brown sugar as it has extra moisture and will result in a denser cake. The brown top comes from the caramelization of the sugar. The bubbles will happen if you are beating the eggs at a high speed, make sure you beat them on a medium speed as this will prevent any large air bubbles from forming
Woohoo! I did it - made it for a friend who likes castella cake, but saying that it's too expensive haha. I failed my first 8 egg whites because I was lazy with the washing and impulsively decided to pour the egg whites in the bowl where I made the milk/butter mixture -- turns out it was AN UNFORGIVABLE BLUNDER! I managed to make the egg whites foamy, but when I added the sugar, it doesn't form merginue! (Lessons learnt the hard way) :'( So I used all my eggs in the fridge to make another batch of merginue. PHEW! It worked! I'm so happy with my results! Thanks for another fail-proof recipe,Catherine! I've been a huge fan of your cooking for so long! Just wondering, I don't think the recipe says where we add the vanilla extract? Anyway, I added it into the egg yolk + batter mixture 😉 Thank you so much!
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Hi Christina, Yes that is the perfect place to add the vanilla extract. So glad it turned out well!!
Hello. I have oven with only fan. What temperature I can use it?
The same temperature will be fine 🙂
Hello! Looking forward to try this recipe! Should I add baking powder?
Thank you!!
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Hi Mayra, no need to add baking powder. The eggs will help the cake rise 🙂
Hey am I able to make this strawberry flavoured by any chance?
Hi Samiha, Yes you could add in some freeze-dried strawberry powder for a fruity flavour 🥳
Do you have any rough guideline of how long to whip the egg whites for in terms of minutes? My cake always cracks and this seems to be the most possible reason, but it's hard to get it to the right level. Thanks.
Hi Tammy, it'll change according to the speed of your electric mixer, as everyone's is slightly different. Cracking usually occurs if the meringue was beaten on a high speed, or if the oven temperature is too high. Make sure you beat your egg whites on medium speed! Hope that helps 🙂
What is the size of the pan?
I used an 8 x 8 inch or 20 x 20 cm pan 🥰
What temperature should I bake at?
140C/285F 😊
Hello! Can this be made in a cupcake style instead of one large cake? I am going to (try to- lol) make it regardless but I will be serving co-workers and having them in an individual wrapper just makes things easier. Thank you!
Hi Heather! Yes I'm sure they can although I haven't tried it before. There is quite a lot of batter so you might need to divide it between more than a dozen cupcake patties and bake it for about 15-20 minutes 😊
Hi Catherine!
My question is in regards to the type of flour used. Some people make this with cake flour, noting that it yields a softer texture. Do you think AP flour with it’s higher protein content is necessary to maintain the structure of the cake? Do you have any experience using cake four with your recipe?
Hi Michael! Such a good question, I found that it does yield a softer cake, however, it deflates a lot faster and is prone to sinking. All-purpose flour here still produces a soft and tender cake so I recommend using that!
My cake was fluffy on the top, but dense at the bottom (still delicions though). What did I possibly do wrong?
I tried the recipe but over 3 hours in the oven a the cake was still raw. Don’t know what I did wrong.
It sounds like the eggs weren't beat to the right consistency, this causes the cake to deflate and have that gummy-like, raw texture. When making this again be careful with how you whip the egg whites and fold them carefully into the rest of your batter. Hope that helps!