It seems like the craze for castella cakes is unlikely to die down anytime soon.

Within the past two months, no fewer than three brands have started selling the popular Japanese-inspired fluffy sponge cake. They include two-month-old Le Castella from Taiwan, bakery chain BreadTalk and its sister brand The Icing Room, and Rious Gold Cake from Indonesia, which did a pop-up at Takashimaya Singapore's Basement 2 Food Hall last month.

And come Friday, another brand - Ah Mah Homemade Cake from Malaysia - joins the competition with an outlet at Bukit Panjang Plaza. Its next outlet is slated to open on July 20 at VivoCity.

Castella cakes (Kasutera in Japanese) are said to have originated in Nagasaki, Japan. Its history, however, started in Portugal.

It is said that the cake was brought by Portuguese merchants to Japan in the 16th century and the castella name is derived from the Portuguese name - Pao de Castela - which means "bread from Castile". In Portugal, sponge cake is also known as Pao de Lo.

In Japan, castella cake is made with flour, sugar, eggs and starch syrup and usually sold in long boxes. It is traditionally baked in a wooden tray - said to keep in moisture - instead of the usual metal baking tray.

The Taiwanese have their own version of the cake, which uses similar ingredients - but it is lighter and fluffier, almost like a chiffon cake. Each portion is branded with the company's logo. A similar version has become a hit in South Korea as well.

The castella cake that has made its way to Singapore is the Taiwanese version popularised at night markets. Le Castella and Ah Mah Homemade Cake each offer two flavours - original and cheese. Their cakes are baked and sliced on-site.

According to Ah Mah Homemade Cake's head chef Jim Wong, the Japanese version is baked for 90 minutes and with some using honey in the batter. The Taiwanese version is baked for up to 80 minutes. It is lighter because the eggs used are separated. The whites are whipped to a fluffy meringue, while the egg yolks are mixed with flour to form a batter.

Mr Wong says that from what he knows, whole eggs are used for the Japanese castella, without separating the whites from the yolks.

The Malaysian pastry chef has been baking since the age of 17 and has worked at various bakeries in Malaysia, Brunei, Singapore and Taiwan. He learnt the recipe for Ah Mah Homemade Cake from a Taiwanese chef.

While the ingredients are common, it is not necessarily easy for someone to recreate the cake at home, says Mr Wong, 33.

Wearing a long glove that goes up to his elbow, he dunks his arm into the mixing bowl to mix the meringue and egg yolk batter by hand. He says in a mix of Mandarin and English: "It's all about feeling to get the right consistency, no machine can do that."

When the cake is baked, he pulls it half out of the oven and gently touches the top - again to "feel" the texture.

He says that for home bakers who do not have industrial-sized ovens, the cakes will be smaller and are likely to dry out easily.

Ah Mah Homemade Cake is brought in by Ms Serene Ang, 40, who holds the franchise in Singapore. She also runs Snackz It, a chain of kiosks specialising in fried finger food.

She says: "The simpler the cake, the tougher it is to perfect the technique. The cake is not fancy. It has no cream and no butter. It is a taste of tradition."

She does not plan to bank on just one cake, but will add traditional cakes to the shop's offerings.

By the end of this month, Ah Mah Homemade Cake will hit 19 stores in Malaysia, where the brand started just three months ago.

Ms Ang also plans to open in Wuhan, China, followed by Thailand and Australia - all in the next two months.

At Le Castella in Tampines, franchise owner Adam Ahmad, 25, says its opening in May was met with "overwhelming" response. Customers queued for up to five hours. Now, a system is in place offering three time slots for placing orders.

He noticed the castella craze last year, when the cakes started going viral on social media.

He went to Taiwan with his business partner to taste the cake at various stores before picking Le Castella. He says: "The cakes are baked at constant heat for about 80 to 90 minutes. If the cakes are over-baked, they'll go flat and dry, so our kitchen staff have to constantly watch them. Certain ingredients are imported to ensure consistency with the cakes in Taiwan."

This is his first food and beverage venture and he still works in his family's palm oil logistics business. He is already planning a bigger second outlet and is busy training staff to handle operations.

Just one day after Le Castella opened, local bakery chain BreadTalk brought out its version of the castella on May 11. It is called Pong Pong Cake and has a layer of salted egg yolk.

It is available at selected BreadTalk and The Icing Room outlets and the recipe comes from its Taiwanese chef Tseng Wen Jun. The cake's name alludes to its fluffy texture.

Another brand which may set up shop in Singapore is Rious Gold Cake, following the success of its recent pop-up stall. Its products, which look more like Japanese castella, are branded as a "reinvention of the Japanese castella cake". Flavours include pandan kaya, strawberry and matcha, in addition to the original and cheese flavours.

The cake craze has met with mixed reviews from customers, many of whom are sceptical about the hype over what seems a simple cake.

Sales executive Candice Ho, 28, says: "I was wondering what the fuss over Le Castella was about. I tried it because my friend bought the cakes and I don't think it tastes particularly outstanding. But it is very fragrant.

"I didn't buy any cake when I was in Taiwan recently. I guess what draws people is that it is freshly baked. And people will queue for anything new."

Housewife Germaine Lim, 45, however, likes the cake. She says: "I was initially attracted by the queues at Le Castella, but who has the time to wait for many hours? But now that it has a better system, I can run errands while waiting for the cakes. I think people are very fascinated watching the cutting of the cakes. I am too. I like that it is freshly baked. And it makes for a nice tea break or breakfast for my children.

"I'm looking forward to new brands coming in. The queues will die down and I can buy the cakes more often."

•Follow Eunice Quek on Twitter @STEuniceQ

Where to buy

LE CASTELLA

What: The Taiwanese brand made waves when it launched here in May - for attracting long queues that often meant a five-hour wait. Now, the situation has improved, with a system that allows orders to be placed at 11am, 4 and 7pm. Each customer is limited to two cakes. Two flavours are available - original ($9.90) and cheese ($11.90). There are plans to introduce a chocolate flavour that is available in Taiwan, as well as a locally inspired cake for National Day.

Where: B1-32 Tampines 1, 10 Tampines Central 1, open: 11am to 10pm daily

Info: Go to www.facebook.com/LeCastellaSG or e-mail castellasingapore@gmail.com

AH MAH HOMEMADE CAKE

What: Launched three months ago in Restoran Poh Yap, Kota Kemuning, Malaysia, Ah Mah Homemade Cake has expanded rapidly and now boasts 14 outlets across the country. To date, it has sold more than 100,000 boxes of cakes in Malaysia.

It opens its first outlet in Singapore at Bukit Panjang Plaza on Friday and a second one will open on July 20 at VivoCity. It offers two flavours - original ($8) and cheese ($11, foreground) - and customers can watch the cakes being made on-site. About 500 cakes will be baked every day at the Bukit Panjang outlet and more than 300 cakes at VivoCity.

Where: 01-18 Bukit Panjang Plaza, 1 Jelebu Road, open: 10am to 10pm daily

Info: Call 6325-4508 or go to www.facebook.com/iloveahmahsg

BREADTALK AND THE ICING ROOM

What: One day after Le Castella opened in May, this home-grown bakery chain introduced its own version of the popular cake. Called Pong Pong Cake ($8.80) - alluding to the sponge cake's bouncy texture - it has a layer of salted egg yolk filling. The cake is not available this month because of BreadTalk's anniversary promotions. It will return next month.

Where: BreadTalk outlets at Chinatown, Novena Square, Toa Payoh, Paragon and Westgate; and The Icing Room outlets at Jurong Point and Nex, various opening hours

Info: www.facebook.com/breadtalksingapore