Preheat the oven to 300°F. Line baking sheets with parchment paper.
Cream butter and sugar in a large mixing bowl using an electric mixer on medium speed until light in texture.
Stir in cornstarch and flour. Mix well.
Scoop into balls by a heaping tbsp (15 mL), I use a small ice cream scoop, on prepared baking sheets 2” (5 cm) apart.
Bake in preheated oven for 15 to 20 minutes, or until very lightly browned. (Time will depend on the size of cookies.) Cool on wire cooling racks.