Insert the butterfly into the bowl and add the yolks and sugar, whisk: 4 min. speed 4.

Remove the butterfly, add the flour and mix: 1 min. speed. 3 and set aside.

In the clean and dry bowl, place the clean and dry butterfly and add the egg whites, whisk: 5 min. speed 3.

Incorporate the whipped egg whites into the set aside mixture gently with movements from bottom to top.

Pour into a baking tray lined with parchment paper (45×37 cm), level with a spatula and bake in a preheated oven at 180 degrees for 10-15 minutes, the surface should be just golden brown.

Take the tray out of the oven and immediately remove the cookie dough from the tray, cover it with a clean towel and turn it over with a quick movement.

Remove the baking paper very gently and cover it with another clean towel, also folding the sides underneath, so as not to let air in.

Let it cool for at least 2 hours at room temperature (covered). This step is to keep the dough elastic and therefore perfect for rolling.

After two hours, the cookie dough is ready to be used, remember that the brightest part will be the outside and then spread the filling on the other side... Buon appetito!