Soletilla sponge cake

For this recipe, the following preparations are necessary:

• Preheat the oven to 180 ° C (3-4-3)
• Separate the  egg whites from the yolks.
• Whisk the whites with a pinch of salt.
• When they foam, add half of the sugar and keep beating until stiff.
• Beat the yolks with the other half of the sugar.
• Add the pre-sifted flour to the yolks and fold in with a silicon pastry spatula.
• Add the beaten egg whites and fold the whole mixture with the silicon pastry spatula.
• Pipe the mixture onto a baking  parchment in long strips and sprinkle with anti-humidity icing sugar.
• Bake for 15-20 minutes.
• Once cooked, place on a cooling rack.