Butter Crunch Cookies

Butter, icing sugar, cornflour and cake flour, chilled and baked slowly into a crisp, short cookie. No country is named and none applies: this is a shortbread-type biscuit of the kind made everywhere. The cornflour is what does the work, and it is worth understanding. Cornflour has no gluten and no protein structure, so replacing over half the flour with it produces a cookie with almost no chew at all, it crumbles and dissolves rather than snapping. That is the crunch of the name, and it is closer to a Scottish shortbread or a Chinese cornflour cookie than to a chewy butter biscuit. Two details in the method matter. The dough is refrigerated for thirty minutes before shaping, which firms the butter so the cookies hold their form rather than spreading. And they are baked at a low temperature for a long time, around forty to forty-five minutes in a cool oven, which dries them out rather than browning them. That length at that heat is what produces the texture, and it also means they should be watched, since a cookie this pale gives little visual warning before it colours.