Mix the flour, cornstarch, sugar and a pinch of salt in a bowl, add the warm butter or margarine in small pieces and knead the mixture until the dough has a smooth consistency. Aromatize with orange, tangerine and vanilla, knead well again and leave to rest for about 30 minutes in the fridge. Put the dough in the freezer for about 20 minutes. Then roll out on the floured work surface, cut out cookies and place on a baking tray lined with baking paper. Preheat the oven to 160°C and bake for about 20-25 min. until crispy light brown and let cool.