Mix the flour well with the cold butter and sugar. Then add the egg yolks, the whole egg, a pinch of salt and a little grated lemon zest. Knead well, but quickly because otherwise the butter gets too hot.
Make rectangular cakes and cool them quickly in Freddy with the blast chilling function for about 1 hour. Cut the dough into slices and, with the work surface floured, make snakes of about 1 cm in diameter, then cut into strips of the length of an index finger, give the strips the shape of "S".
Bake for 10-12 minutes at 170ºC. Then cool the cookies with the function of blast chilling of Freddy for about 90 minutes.