A homemade castella sponge cake that's more moist than store-bought cakes. Depending on how you cool it after baking, the finish will be light, like the kind you could get at an old fashioned sweet shop, or authentically moist like the ones sold at high-end traditional wagashi (traditional Japanese confectionery) stores.
100 g (if the eggs weigh 200g. If the eggs are 220 g, add 10 g of sugar)
Bread (strong) flour
100 g (if the eggs weigh 200g. If the eggs are 220 g, add 10 to 20 g of flour)
※ Raw cane sugar (optional)
Line a baking pan with parchment paper, and sprinkle raw cane sugar. You can omit the raw cane sugar, but if you want a rough and crunchy texture on the surface like the store bought type, add it.
Heat eggs and sugar in a double boiler or in a bowl suspended over a pan of hot water. Combine the ☆ ingredients in a cup.
Beat the eggs and sugar over hot water at high speed with a handheld mixer until the mixture is a bit warmer than body temperature (about 110°F/43°C if you have a thermometer).
When the egg-sugar mixture is about 110°F/43°C, take it off the hot water and keep on beating at high speed. Heat the combined ☆ over the hot water in the meantime.
Keep beating for a total of 10 minutes at high speed, until the batter forms ribbons when lifted. Mix at low speed to even out the texture.
Add the warmed ☆ ingredients, and beat at low speed for about a minute.
Add 1/3 of the bread flour while sifting, mixing at low speed. Sift in the remaining 2/3 of the flour. Beat at low speed for a total of a bit less than a minute.
Don't overbeat the batter, just beat for about a minute noted in step 7. If beating the batter creates lines on the surface, as shown in the picture, and there are no lumps, it's done.
Preheat the oven to 350°F/180°C. Pour the batter into the lined and sugar scattered baking pan. Hit the pan lightly on the countertop, and draw lines through the batter up, down, left and right to eliminate air pockets.
When the oven has reached the right temperature, lower the temperature to 340°F/170°C and bake the cake for 10 minutes. Lower the heat again to 285°F/140°C for 45 minutes.
If you cool the cake out in the open, it will have a light texture like the type of castella sold at an old fashioned sweet shop. For a moist texture, take the cake out of the pan as soon as it comes out of the oven and wrap it completely with plastic wrap.
Put the wrapped cake in a plastic bag or container large enough to hold the whole cake. Leave at room temperature for more than a day.
If you leave it for 2 days without unwrapping, the top may peel off as shown here. But the texture will be dense and moist, like a high end castella from a traditional Japanese confectionery.
To slice the castella, use a warmed knife and move it in small strokes for a nice cut surface.
It's light and airy the day of baking, but moist and just like what you'd get from a high-end confectionery style castella after 2 days. Try and see what you like best!
Story Behind this Recipe
My husband requested this, plus I wanted to use up a lot of eggs that were nearing their best-by date . Challenge yourself to make homemade castella!
As I wrote in the directions, if you don't let the castella steam in plastic wrap, you will have a light, old-fashioned sweet shop type castella. If you wrap it up tightly and let it sit it for more than a day (I let it sit for 2 days) you'll have a moist, densely textured 'traditional confectionery shop-style' castella.