Golden Sponge Cake

My favorite sponge cake, recipe adapted from here.

Ingredients (*6" or "" round cake pan with removable base - cannot use non-stick)

50g butter (salted)

50g cake flour
3 egg yolks
55g milk

3 egg whites 

50g caster sugar
6g corn starch

Method

1. Prepare a cake pan, don’t need to grease or line paper.

2. Separate egg white and egg yolk into two mixing bowls. 

(if I wanna bake last min, I will soak the chilled eggs in warm water to speed out the process to room temperature)
3. Melt butter in a saucepan, once you see small bubbles, remove from heat.
4. Immediately add in sifted flour, quickly stir to become batter. (the batter is like very soft paste)
5. Pour the milk into a empty mixing bowl, scape in the butter + flour batter and mix well with the milk. (like mayonnaise kind of texture)
6. Add in egg yolk one at a time, stir well on each addition. The batter is slightly runny if compare to normal chiffon batter. (I added in all egg yolks at once, the batter is runny)
7. Mix sugar and corn starch together. Beat egg whites till foamy, gradually add in sugar and corn starch mixture (three times) and continue beat until approaching stiff peaks (meringue stand straight up with a little curve at the tip) or till stiff peaks (this stage is a bit difficult to fold with egg yolk mixture)
8. Take 1/3 of meringue and use a hand whisk to mix well with egg yolk batter.
9. Fold in 1/2 of meringue and use a silicone spatula, gently fold with egg yolk batter till slightly combined. Fold in the balance meringue and gently fold till well combined. 
10. Pour the batter from high slowly into cake pan to release bubbles, then lightly bang the cake tin to further release the bubbles.

11. Bake at pre-heated oven at 140C (no fan) for 25mins at low rack, then increase to 170C (no fan) for another 25mins. (for my oven I baked in 100C for 30 mins and 150C for 20-25 mins)
12. Remove the cake pan from oven, drop it from high side to prevent the cake shrink too much during cool process.

13. Turn the cake pan upside down and cool completely before remove from the cake pan. (I turned the cake pan and use 2 cups to support the side of the cake pan, this is to prevent the cake top with the wire mash printing.)

Important tips to get this sponge cake right:-

1. bake it over low temperature first then later increase temperature to medium, and always bake it at the lower rack. So the cake will not shrink at all after it gets cool.

2. Also you need to have stable meringue which requires you to beat till stiff ..Don't worry stiff meringue created dry cake texture, because the batter is using 烫面 "Tang Mein" method (that means cook the egg yolk batter first).