This recipe is indeed the best I used for biscuit cake. It is working every single time! The sponge is very fluffy and airy, perfect for whatever cream you want to spread on it. You don’t need to spread any kind of syrup on it because it is perfect as it is.
Preheat the oven 175° C, ventilation
Grease the tin with butter and sprinkle with flour.
Separate the egg whites from egg yolks.
Grate the lemon zest.
In a separate bowl, mix the flour with the cornstarch and baking powder.
Beat the egg whites with 50 g sugar until stiff.
In a different bowl, create the egg yolk cream:
mix the egg yolks with the lemon zest, add the lemon juice from half of the lemon together with the remaining sugar (60g) and vanilla sugar, and mix around 4-5 minutes until a creamy mixture forms.
Carefully, fold the egg whites into the egg yolk mixture with a pastry spoon.
Sift the flour mix over the top and fold in carefully.
Fold the fluffy cream into the tin and bake for 20-25 minutes.