Preheat the oven to 325 degrees F. Place the butter and sugar in a bowl and beat until light and fluffy. Sift the flour, cornstarch and cinnamon into a separate bowl, then gradually work them into the creamed mixture with a wooden spoon. When well mixed, knead until smooth. Take 1 teaspoon at a time of the dough and roll into little balls. Place them on the cookie sheets and bake in a preheated oven for 15-20 minutes or until pale golden on the bottom. The smaller the balls the better! Sift the confectioners sugar into a shallow bowl or pie dish and toss the cookies in while they are still warm. Let cool on parchment paper.