Mix the flour, cornstarch and powdered sugar together and sift into a bowl. Add the vanilla sugar and butter in pieces and knead everything into a shortcrust pastry. Shape the dough into a ball, wrap in cling film and refrigerate for about 30 minutes.
Shape the dough into walnut-sized balls (I use between 30 and 36 pieces) and place them on a baking sheet lined with baking paper. Press the cornflakes on the sides as ears, place the chocolate chips in the middle as a nose and use the sprinkles to shape the eyes.
Bake in the preheated oven for about 25 minutes at 160 ° C.