In a bowl mix the flour, cornstarch and salt. In another bowl whisk the butter, sugar and vanilla until a fluffy mixture. Then added and the mixture of the dry ingredients and the whole was kneaded to give a shortbread. Form a ball and place it covered in the refrigerator at least one hour or until set. The oven is preheated, the solid dough make small balls (about 2.5 cm) and baked 12-14 minutes at 180 C. Allow to cool for about 5 minutes and rolled in powdered sugar. From such a dose producing about 36 sweet.