one of the most satisfying aspects of a good ginger snap sugar or chocolate crinkle cookie is the small cracks on the cookie's surface in the case of chocolate crinkle cookies these fissures literally make the cookie they provide a contrast of bright white powdered sugar and dark chocolate crinkles the key to getting cookies with attractive cracks is the right combination of surface drying and spread does it sound simple well it's actually a hard balance to strike if a cookie spreads rapidly before the surface dries sufficiently you end up with gaping sparse cracks like this cookie here the opposite is also problematic the surface on this cookie dried quickly but the cookie didn't spread enough to properly rupture the surface and crack so how do you guarantee perfect cracks every time to efficiently dry the surface of a cookie it's crucial to bake one sheet at a time now this ensures that all the cookies are exposed to the drying radiant heat reflecting off the top of the oven you can see what happens when we try to stack two sheets of ginger snaps the cookies on the top sheet crack nicely while the cookies on the bottom tray only wrinkled for crinkle cookies we took things a step further by using granulated sugar in addition to the traditional powdered sugar on the exterior sugar is hygroscopic which means that it can draw moisture from the surface of the cookies as they bake this water then dissolves some of the sugar creating a sugar syrup as baking progresses water in the syrup is evaporated in the dry heat of the oven which concentrates the sugar syrup to the point that it recrystallizes trapping additional water in its crystal structure at this point the surface is dry enough that the process stops the upshot of this transformation a cookie with a fast drying surface that is prone to cracking to nail down just the right amount of spread you need to control both leavening and temperature the right combination of baking powder and baking soda creates cookies that not only rise but also spread to the right degree baking soda raises the ph of cookie dough which actually weakens the gluten structure providing for more spread it also produces more carbon dioxide gas than baking powder alone excess gas exits the surface of the cookies as they bake helping to create fissures you can see this difference in these two sugar cookies this one contain only baking powder and formed a wrinkled dome shape on the other hand this cookie combined both baking powder and baking soda it's spread properly and features a network of small fissures now the temperature of the dough when it goes into the oven has a huge impact on spread refrigerated dough will spread less than dough at room temperature because it takes more time for the butter to soften and melt during this time the exterior of the cookie sets in the heat of the oven the correct formula for our chocolate crinkle cookies we started with dough that rested for 10 minutes at room temperature which gave more spread than refrigerated dough but less than dough that is baked immediately after mixing and used both one teaspoon baking powder and a quarter teaspoon baking soda baking one sheet at a time at 325 degrees delivers the perfect chocolate crinkle cookie every time this is the signs of good cooking