Sponge cake in a large pan

Take the 10 eggs at room temperature and then separate the whites from the yolks. Whip the egg whites with an electric whisk and add a pinch of salt
and the seeds of a vanilla pod, whisk until the egg whites are nice and frothy. Whip the egg yolks.

In the bowl with a egg yolks add the sugar, then add the flour and the already sifted potato starch.
At this point the mixture begins to become a little dense so use a spatula to mix and then add the whipped egg whites, mixing delicately from bottom to top, everything must remain very frothy. Grease and season the baking tray. Gently pour the homogeneous paste and level it slightly with the help of the spatula.
Use a zippered pan. Bake for 50 minutes in a low oven at around 160°C.

Once cooked, let it cool, then first detach the sponge cake from the edges and then turn it upside down on a flat surface and delicately cut into crescents, so you will obtain 2 layers to fill.
You can fill it with creams and jams as you like.
Happy filling!!