How to make Korean castella cake (honey sponge cake) using pre-mix.

One of my childhood favourite snacks is castella cake (honey sponge cake). It’s sweet, soft and a well made version of it melts in your mouth!

My mom used to use this cake when she made some sweet rice cake balls (Gyeongdan 경단).

Back then, I didn’t know that the origin of castella was Nagasaki, Japan. (In Japan, castella cake is called kasutera and in Korea we call it 카스테라 빵.) Regardless, castella is a very popular cake / bread in Korea and many people like it.

Conveniently, there is also a pre-mix version of castella you can try as well.

I only found out about it a few months ago. I was very delighted because even though the real ingredients that go into this cake seem simple, many people said that it is a quite a difficult cake to bake from scratch. So why not try a pre-mix version?!

As far as I know, there is only one Castella pre-mix brand in Korea and it is called Beksul Castella Mix by CJ. CJ’s popular bakery brand Tous les Jours is also involved in product development as well.

Unfortunately, they don’t have English instructions for this cake mix, so I thought I will translate it for you.

Though just want to comment that as with many Korean manuals, there was some ambiguity in the instructions, so I added my personal tips and comments based on my own experiment at the end.

Here it goes.

Product Info & A List of Other Ingredients and Tools You Will Need

Product name – Beksul Castella mix (by Tous les Jours)
Made by – CJ
Purchase price – around AUD $4.00 at a Korean grocery store (under 3,000 won in Korea)
Weight – 300g (This packet gave me about 8 to 10 medium sized slice of Castella.)
Contents – Flour mix 100g (2^nd from the left in the photo), Sugar mix 140g (3^rd ) and Corn syrup 60g (4^th )
Difficulty level – Hard (written on the back of the box)
Other ingredients you need to supply
- 3 large eggs
- 1 egg yolk
- 20 ml milk
Baking tools you need
- Large kneading / mixing bowl
- Hand mixer
- Sieve
- Baking spatula
- Baking paper
- Cake tray

How to Make Korean Castella Cake Using Mix (per Manufacturer)

Add 3 eggs, 1 egg yolk, sugar mix 140g and corn syrup 60g into a kneading bowl and mix them with a hand mixer on high speed for 5 to 6 mins.
Add the Flour mix 100g into the bowl above (step 1) and quickly mix it in with the spatula. (If you mix it for too long, the Castella can get chewy, so watch out.)
Add the milk and mix well.
Pour the dough into the cake tray (cover up 2/3 of the tray) and bang the cake tray on the board lightly a couple of times to remove air bubbles.
Put the cake tray in the bottom of the pre-heated oven and bake it at 150C to 170C for 30 to 40 mins. (Adjust the time by checking the cake during the baking as it will be different depending on the type of the cake tray and the oven.)
Take the Castella out and cool it down. Serve.

Manufacturer’s Tip:

For best taste

Use hand mixer if you like to taste “authentic” Castella.
You can enjoy the extra moist Castella if you eat it after wrapping it with glad wrap for 2 hours once the Castella completely cools down.
You can also decorate the cake with freshly whipped cream and fresh fruit (e.g. strawberries)

For convenience

Pre-heat the oven at 150C (300F).
Take out the eggs and leave them at room temperature for 30 mins.
Place the baking paper on the cake tray before you start making the mixture.

My Tips and Suggestions

I pre-heated my oven at 170C (325F) for 10 mins. (I have an electric oven with 56L capacity and it’s not fan forced.)
Sieve the sugar mix (from step 1) and the flour mix (from step 2) before adding them in to avoid any lumps.
The setting for the hand mixer I used was high (ranges between low and high) and speed 3 (ranges from 0 to 5, with 5 being the highest).
I baked the Castella at 160C (320F) for 40 mins.
I cool the cake on a rack (still in the baking tray) for 20 mins.
It goes very well with warm milk.

My Outcome

Appearance

Crust is not as dark as the picture on the box and also it had a somewhat crater looking surface.
The Castella shrunk a lot while it was cooling down. It got wrinkly to some degree so it looked less appetising compared to when I first took it out of the oven

Texture and taste

It was thoroughly cooked overall (no undercooked or overcooked area) and it was soft. However, the top and bottom crust was a bit sticky and it didn’t stay on the cake. Meaning as I was cutting the slices, the crust got stuck to my fingers.
It tasted just like I remembered it should be.

My Verdict

I thought any pre-mix version of cakes or cookies are easier to work with and you can always expect an above average outcome.

But, this one wasn’t easy! (I also read a lot of people failed to work successfully with this mix on the internet and more closely I saw my sister making literally “uneatable” Castella a few weeks back and we ended up throwing most of it away. For your information, she cooked it on 170C for 30mins and it was undercooked inside and burnt outside!)

I was also very curious how CJ managed to display such a successful looking Castella cake on the box cover. Maybe with help from Photoshop? 🙂

Regardless, it is a very convenient way of creating an instant Castella cake. But, I’m sure it can’t beat the real Nagasaki Castella particularly in texture and taste!