Sponge cake is the base of many cakes. I tried different recipes, and I like the lightness of this sponge cake. To get the light fluffy texture, please do not skip baking powder. You can use this recipe for a roll cake using about 28x28cm square pan.
I attached the original recipe in Japanese.
If you want to make a cocoa sponge cake, simply swap 15% of the total flour into cocoa powder, you can do with 10g of cocoa powder and 70g of plain flour. For Matcha flavor, please swap 5% of flour into Matcha powder.
Ingredients (18cm round baking pan)
80g of plain flour, sifted
1/2 teaspoon of baking powder, sifted
3 eggs
80g of sugar
20g of butter
1 tablespoon of milk
Instruction
1. Place parchment paper on the side and the bottom of the baking pan.
2. Add butter and milk in a small bowl and melt them in a bowl of hot water.
3. Preheat the oven at 160C.
4. Whisk eggs with an electric hand mixer, at low speed about for 30 secs. Add about 1/3 of sugar, and whisk for 30 secs, add the half of the remaining sugar and whisk for 30secs,then add the remaining sugar and whisk for 30 secs all at low speed. Keep low speed so the egg mixture becomes smooth and creamy without large holes.
5. Run a hand mixer at medium speed for 3 mins, then turn up to high speed and whisk for 2-3 mins. When it looks pale, with the mixer, check the mixture by scooping and dropping it to see if the trace remains for 4-5 secs. Whisk for 2 mins at the lowest speed.
6. Add half of sifted flour and baking powder through a strainer to the bowl, and fold with a rubber spatula. (In this way, you are sifting flour twice, and it will give more consistent softer sponge.) When there is no flour bits, fold the remaining flour and baking powder into the mixture.
7. Add the mixture of warm milk and melted butter to a bowl by making a thin streak so that it goes everywhere evenly, and fold in with a spatula until you see no butter streak. This step should be quick and do not over-mix.
8. Pour the mixture into a baking pan, and drop the baking pan from 10-20 cm above, 5-6 times to remove large air bubbles.
9. Place the rack at the low level and bake at 160C for 30-35mins. When the top surface is golden brown, check the inside with the toothpick. If it is baked, take it out from the oven.
10. To avoid getting shrunk, drop the bake in the pan from 10-20cm above, a few times. Then take the cake out from the pan, remove the paper on the side, flip the cake up-side-down then leave it on a cooling rack for 3 mins. Flip the cake up-side-down again so that the original top surface is facing up, cover with a slightly wet tea towel until it becomes around room temperature.
11. Cover with a plastic wrap until it is used. (I often bake this a day before serving with decoration.)
Link to the original Japanese website- https://www.orangepage.net/recipes/detail_127402